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Erlandsson, Marie. "Överbelastningsproblem för avloppsledningsnät och kostnadseffektiva åtgärder : En fallstudie med förenklad hydraulisk modell." Thesis, Uppsala University, LUVAL, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-128865.
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<p>Många svenska kommuner har idag problem med överbelastade avloppsledningssystem. Det kan bland annat resultera i källaröversvämningar i närbelägna fastigheter, överbelastade reningsverk eller bräddningar till recipienten. För att motverka dessa effekter kan olika åtgärder vidtas. Åtgärderna kan vara olika lämpliga beroende på typ av område och kostnaderna för genomförandet kan variera kraftigt och ha olika miljöpåverkan. Detta innebär att det är viktigt att väga samman effektiviteten av olika åtgärder, deras miljöpåverkan, kundnytta och kostnad.</p><p>Syftet med examensarbetet var att med hjälp av ett hydrauliskt modelleringsverktyg (PCSWMM) studera ett antal typområden och ta fram en förenklad modell. Modellen ska enkelt kunna anpassas till olika områden och ge en översiktlig bild av situationen i områdets ledningssystem. Därmed kan eventuella överbelastningsproblem lokaliseras och en kostnadseffektiv lösning testas.</p><p>En hydraulisk modell utvecklades för Viksängsvägens avrinningsområde i Södertälje kommun. Det är ett äldre område med underdimensionerade ledningar vilket orsakar problem vid hård belastning. Effekten av olika åtgärder testades i modellen och en kostnadsanalys gjordes för att utreda vilken åtgärd som var mest kostnadseffektiv.</p><p>En grenad modell visade sig ge bäst beskrivning av Viksängsvägens avrinningsområde. Det var en förenklad modell som gick relativt snabbt att sätta upp för ett nytt område och som tog hänsyn till avrinningsvolym, ledningskapacitet och ledningssystemets struktur. Modellen kräver dock en del information om ledningssystemets uppbyggnad och de hårdgjorda ytornas fördelning över området.</p><p>Den åtgärd som rekommenderades för Viksängsvägens avrinningsområde var att bygga utjämningsmagasin i anslutning till Viksängsvägen. Detta för att kostnaden var relativt liten jämfört med andra åtgärder samt för de positiva effekter åtgärden har på miljön och människorna som bor och vistas i området.</p>
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Kjellander, Kalle. "River-Aquifer Interaction in the Uppsala Esker - a Modelling Study of a Proposed Drinking Water Production site." Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-355671.
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The Swedish municipalities of Gävle and Älvkarleby need new sources of drinking water as the population grows. Gästrike vatten AB has employed the consultant firm Midvatten AB to assess the possibility of a new groundwater extraction site on the Uppsala esker between Älvkarleby and Skutskär in northern Uppland county. It has been observed that the natural recharge to the aquifer in the Uppsala esker might be too low to compensate for a future groundwater extraction and that there is a risk of induced infiltration from the river Dalälven if the water table is lowered. River water might bring organic contaminants into the aquifer and negatively affect the groundwater quality.A solution proposed by Midvatten is to infiltrate the esker with river water free from organic contaminants at infiltration sites. This artificial infiltration is estimated to create new groundwater to compensate for the extraction and stop river water from reaching the extraction wells. There is however, a need to estimate the magnitude of infiltrating river water when the infiltration sites are active.The aim of this study was to estimate the flow of water between the river and a section of the Uppsala esker for a test period during 2017, specifically, the infiltration from the river. In addition to this, changes in flow depending on proposed pumping and infiltration scenarios were modelled.A MODFLOW model was developed in the graphical user interface Groundwater Modeling System (GMS) and its performance was validated against observed aquifer head. The model could accurately represent the head close to the river but was less accurate with increasing distance from the river. Average infiltration from the river varied from 3 to 25 l s-1. The calculated infiltration depended on which extraction well or artificial infiltration site was active and the rate of flow.It was concluded that the distribution of hydraulic conductivity in the aquifer was not sufficiently detailed. A solution could have been to use stratigraphic data from borehole logs instead of a general quaternary deposits map as basis for the distribution of hydraulic conductivity. Artificial infiltration close to the river prevented large volumes of induced infiltration. The accuracy of the model could have been improved if the results were compared to other methods such as particle-tracking, tracer tests and with measurements of the streambed such as seepage meters.<br>Gävle och Älvkarlebys kommuner är i behov av nya grundvattentäkter för att kunna försörja invånarna med dricksvatten i framtiden. Ett område som är av intresse för de två kommunerna är ett grundvattenmagasin i Uppsalaåsen intill Dalälven mellan Älvkarleby och Skutskär. Vid ett dricksvattenuttag kan vattenbalansen i magasinet ändras. I magasinet uppskattas grundvattenbildningen vara för låg för att pumpa upp nog mycket vatten och bibehålla en stabil dricksvattenförsörjning. När uttaget av grundvatten är högre än grundvattenbildningen sänks grundvattenytan och vatten flödar från andra delar av magasinet eller älven för att kompensera. Älvvattnet bedöms ha en stark hydraulisk koppling med grundvattnet, vilket innebär att det finns en risk att älvvattnet infiltrerar i magasinet och sänker kvalitén på framtida dricksvatten.Konsultföretaget Midvatten AB har i uppdrag att bedöma möjligheten till ett framtida dricksvattenuttag. Midvatten har som lösning anlagt stationer med sprinklerinfiltration för att i framtiden kunna infiltrera avhumifierat älvvatten som på sikt omvandlas till grundvatten. Denna konstgjorda infiltration är också tänkt att hindra älvvatten från att ta sig in i magasinet genom att förse magasinet med den mängd vatten som går förlorad av dricksvattenuttag. Hur mycket älvvatten som tar sig in till grundvattenmagasinet och når brunnarna vid ett framtida uttag och konstgjord infiltration, är dock oklart.Syftet med denna studie var att uppskatta flödet mellan åsens grundvattenmagasin och Dalälven och specifikt infiltrationen av älvvatten. Detta gjordes genom att utveckla en digital MODFLOW-flödesmodell i programmet GMS. Modellen kunde, med hjälp av uppmätta vattennivåer i grundvattenmagasinet och älven, räkna ut hur mycket vatten som flödade in från älven (infiltrerade). Den uträknade infiltrationen låg i genomsnitt på 3-25 l s-1. Infiltrationsmängden berodde på vilken brunn som vattnet pumpades ur, hur mycket som pumpades ut och hur mycket artificiell infiltration som tillfördes i de tre infiltrationsområdena under en period av 2017. Modellen användes även till att uppskatta flödet från älven för 28 tilltänkta scenarier under 2017 med konstant pumpning och konstgjord infiltration i de olika brunnarna och infiltrationsstationerna.Resultaten visade att modellen kunde uppskatta grundvattenmagasinets vattennivåer nära älven men inte på längre avstånd ifrån älven. Detta berodde på att magasinets hydrauliska parametrar inte var korrekt fördelade. Fördelningen kunde ha förbättrats om de baserats på jordarter från borrprotokoll istället för en jordartskarta. Modellen visade att mycket lite älvvatten flödar in i akviferen om vatten artificiellt infiltreras nära älven. För att resultaten av den här studien ska bli tillförlitliga krävs det att resultaten jämförs med andra metoder som använder sig av förslagsvis partikelspårningsmodeller, spårämnesstudier eller flödesmätningar av flodbädden.
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Kuoljok, Simon Pirak. "Konnektivitetsåtgärder i Emån : En fallstudie vid Högsby vattenkraftverk." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298253.
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Den nationella planen för vattenverksamheter antogs år 2020 och innebär att vattenverksamheter ska förses med moderna miljövillkor för att öka vattenmiljönytta och att bibehålla den effektiva tillgången till vattenkraftsel. Emån som är ett Natura 2000-område är det största vattendraget i sydöstra Sverige och vattendraget är utifrån konnektiviteten klassificerat som måttlig. Högsby vattenkraftverk, som ligger i Emån och ägs av Uniper, ska omprövas utifrån miljövillkor enligt den nationella planen och idag har Högsby vattenkraftverk ingen fastställd minimitappning för sin anläggning. Målet med studien är att undersöka storleken på vattenflödet av minimitappningen som kan användas i den ursprungliga naturfåran i Högsby för att möjliggöra longitudinella spridningsmöjligheter i uppströms och nedströms riktning för de fiskarter som historiskt sett har kunnat vandra genom Högsby. En sektion i naturfåran är uppdämd av en tröskeldamm som bedöms vara den svåraste passagen i naturfåran med undantag från utskovsdammen. Metoden som används i rapporten är en endimensionell stationär modellering i HEC-RAS över den naturfåra som kan möjliggöra fiskvandring förbi vattenkraftverk. Två modeller har skapats – med och utan tröskeldamm. Utifrån resultatet är den högsta medelvattenhastigheten i sektionen nedanför tröskeldammen i båda scenarion, detsamma gäller medelvattendjupet. De konnektivitetshöjande åtgärder som diskuteras är minimitappning och olika fiskvägar i naturfåran för att behålla den historiska forsmiljön som funnits. Både rivning av tröskeldamm och fiskväg runt dammen har diskuterats. Därutöver anses havsöring och lax vara fiskarter som med stor säkerhet har kunnat passera Högsby historiskt sett. Högsby är klass 1 i relativt reglerbidrag, vilket bör tas i beaktning vid bedömning av minimitappning. Det finns osäkerheter med modellen, såsom batymetri och randvillkor samt validering av modellen. Därför går det inte med säkerhet att säga att vattendjup eller vattenhastigheter stämmer överens med verkligheten. Slutsatsen är att det inte heller med säkerhet går att säga vilka fiskarter som historiskt sett har vandrat genom Högsby, inte heller en minimitappning kan fastställas som kan möjliggöra fiskvandring för alla fiskarter. Däremot kommer implementeringen av en fastställd minimitappning och fiskvägar öka konnektiviteten.<br>In 2020 the national plan for hydropower plants was implemented in Sweden. The national plan aims to increase the environmental standards for hydropower plants for the benefit of the water body and still maintain an efficient access to electricity originated from hydropower. Emån is the largest river in the south-eastern part of Sweden. The river a Natura 2000 area and it is classified as moderate based on connectivity according to environmental norm for rivers and water bodies. Högsby hydropower plant located along Emån is owned by Uniper and are included within the national plan, which indicate that it needs to meet the environmental standard. Högsby hydropower plant currently has no established minimum discharge. The aim of the study is to investigate a minimum discharge for the natural dry stream located in Högsby to enable higher connectivity for the fish species that have historically been able to migrate through Högsby. The natural stream is downstream the spillway dam in Högsby. Within the stream a weir is considered to be the most difficult passage for fish migration, with the exception of the spillway dam. The method used in the report is a one-dimensional steady flow model in HEC-RAS for the natural stream to investigate the possibility for fish migration past the hydropower plant. Two scenarios have been considered – with and without the crest dam present. Based on the result from the model, the highest mean water velocity is the section below the weir for both scenarios and same applies to the mean water depth. Implementation of a minimum discharge and various fish ways in the natural stream is measures for increasing connectivity that are being discussed which would also maintain the rapids that has existed in the stream. The fish ways that have been discussed is based on the scenarios if the weir is present or not. The fish species that with great certainty have been able to migrate through Högsby historically is sea trout and salmon. Högsby hydropower plant have the highest classified regulation of the hydropower plants in Emån which need to be considered when determining minimum discharge. There are a few uncertainties with the hydraulic model such as bathymetry and the boundary conditions. The model is not validated which means that the water depth and the velocity might not reflect the true values. It is not certain which fish species that have migrated through Högsby historically, nor can an established minimum discharge be said to enable fish migration. However, an implementation of a minimum discharge and the fish ways that have been discussed will increase the connectivity in Högsby.
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Wallin, Tony. "Metoder för identifiering och kvalitetsbestämning av lax- och öringhabitat." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298186.
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Vattenkraftens ska förses med moderna miljövillkor i linje med miljöbalken. Ett av underlagen som föreslås vara nödvändigt inför prövningen är kännedom var det finns strömmande vatten och olika typer av habitat, något som inte finns i alla avrinningsområden. Arbetets syfte var därför att testa och utvärdera metoder som med begränsat underlag kan användas för att identifiera lax- och öringshabitat samt utreda sträckornas habitatskvaliteten. För att genomföra detta genomfördes först en lutningsanalys där vattendragets strömsträckor identifierades genom att utifrån lantmäteriets höjdmodell, bestämma lutningen i vattendraget. Därefter bestämdes beskuggningsgraden vid strömsträckorna genom att studera flygbilder följt av parametrarna vattenhastighet, bredd och djup beräknades med MSB:s hydrauliska modell. På detta applicerades trout habitat score och laxhabitatklass, två bedömningssystem som används för att kvalitetsbestämma habitat utifrån fiskens habitatspreferenser för ovannämnda parametrar. Den predikterade habitatskvaliteten validerades sedan mot redan kända habitat som karterats i fält då vattendraget biotopkarterades. Med lutningsanalysen identifierades strömsträckor där samtliga kända habitat som karterats som bra eller mycket bra identifierades. Metoden fungerade således bra för att identifiera strömmande vatten. Det finns dock svagheter eftersom metoden inte nödvändigtvis säger något direkt om strömsträckornas habitatskvalitet, men tillsammans med andra metoder så som lokalkännedom kan borde den vara till nytta att på ett enkelt sätt få en bra bild över utbredningen av vattendragets strömsträckor. När habitatskvaliteten beräknades vid strömsträckorna underskattades i de flesta fall. Vad detta beror på går inte att svara på utan vidare undersökning, men det finns mycket som pekar på att det är till följd av att den hydrauliska modellens rumsliga skala samt kalibrering. Det finns således stora osäkerheter med att använda MSB:s hydrauliska modell i habitatkarteringssyfte.<br>Hydropower is vital for Sweden. Not only does it provide Sweden with around 40% of the annual electricity production and supply the electric grid with system services, but the energy is also to be concerned as renewable with no greenhouse gas emissions. However, the hydropower plants and its dams create environmental problems for the aquatic life in the lake and streams. Moreover, little to no measures have been implemented as most powerplants come from a time where the concern and requirements for environmental mitigation measures were considered. Sweden’s hydropower is therefore to apply for new water permits in line with the Swedish environmental code, likely to result in many powerplants having to implement mitigation measures to lower their impact on the aquatic life. In this work, data on river habitats must compiled, however, the extent to which this data exists varies between different river basins. In river basins where the level of this kind of knowledge is low there is a need for cost-effective ways to investigate this matter. The aim of the thesis was to test and evaluate methods that can be used to identify in stream habitats for trout and salmon parr and assess the quality of these habitats using data which is highly available for many river basins. First a slope analysis was conducted in GIS, to identify rapids in the study area. The method is based on calculating the average slope along the river using the national terrain model. Once rapids were identified, aerial footage was studied to determine the rate of shadow cast on the watercourse and a free to use hydraulic model was used to calculate water velocity, depth, and top width at the rapid locations. Later, the above-mentioned parameters were combined using two methods, trout habitat score and salmon habitat class, to rate the rapids’ functionality as habitat for salmon and trout parr. Finally, the habitat location and quality of the identified rapids were validated against already known habitats, mapped with conventional habitat mapping methods. Using the slope analysis, all known habitats were identified. However, there were a few uncertainties as several river stretches, not mapped as habitat, also were identified. These wrongly identified rapids were for the most part to be regarded as moderately flat and could be excluded using aerial photographs. When it comes to the predicted habitat quality, it can be concluded that it generally was underestimated when compared to the habitat quality from the habitat mapping. The reasons for this were not fully investigated in this thesis, however much points towards weaknesses related to the hydraulic model as it primarily was hydraulic parameters such as depth and top width that was underestimated. The thesis conclude that the slope analysis is a strong tool when it comes to locating in stream habitats using sparse data and has good potential as a screening tool, but one must be aware of the method’s short comings. The hydraulic model on the other hand, shouldn’t be used in its original form to investigate habitat quality.
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Tranová, Kateřina. "Hydraulická analýza vodovodní sítě městské části Brno - Ivanovice." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265396.
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This diploma´s thesis aims to model the hydraulic model of the Brno – Ivanovice water supply system. The software MIKE URBAN for model hydraulic model of water supply system was used. It was performed a simulation of the various states of loading. The water supply system was assessment of pressure ratios. The outcome of this work is calibrated hydraulic model of water supply system. The appendix consists also of drawings, which represented pressure ratios, which are situated on water supply system. On the fourth drawing is described transparent situation of Brno-Ivanovice water supply system.
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Thiele, Elizabeth Anne. "Culvert Hydraulics: Comparison of Current Computer Models." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1727.pdf.
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Forsberg, Johan. "Model-based study of the energy efficiency of two different types of harvester cranes." Thesis, KTH, Maskinkonstruktion (Inst.), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-156712.
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In today’s forest industry two mechanized methods are used, the Tree Length (TL) method and the Cut To Length (CTL) method. With the Tree Length method, trees are harvested and extracted from the forest as a whole tree to be further processed whereas with the Cut To Length method trees are harvested, branches are removed and the tree is cut to desired length to be extracted by a forwarder. The Cut To Length method is now a day 100 percent mechanized and more and more emphasis is put on efficiency in both harvesting and forwarding the trees. Efficiency can be measured in trees harvested per hour but also in fuel consumption. As an effect, the performance of the machines is in higher demand. Ponsse Plc is a finnish forestry machine company with production in Vieremä where both harvesters and forwarders are manufactured. Cranes and loaders are also made by Ponsse to match their harvesters and forwarders. Ponsse manufactures two designs of harvester cranes; a sliding boom crane and a parallel crane. The different types of cranes have the same reach but with different geometries and weights, which also leads to different momentum of inertia. The purpose of this master thesis is to investigate, from an energy efficiency point of view, the difference in performance between a sliding boom crane, C2, and a parallel crane, C22 by measuring the hydraulic pump’s flow and the rotational energy of the cranes. This has been done by modelling the cranes’ hydraulic circuits and by using 3D-CAD models with mass and inertias in Simulink. More specific, only the crane tips of the cranes have moved along a set trajectory, equal for both crane types. Different range and loads have been simulated. The energy needed for rotating the cranes have been calculated for different crane tip positions and compared. Simulink simulations gave beneficial results for the parallel crane when unloaded and acting at a shorter reach. For longer reach, the sliding boom crane was more efficient. The calculations of the cranes rotational energies showed that the parallel crane C22 yielded higher values than the C2 at shorter distance from the axis of revolution. The C2 crane had however slightly higher values than the C22 crane at longer reach, but it should be noted that differences were small. From this analysis, it is concluded that the C2 crane has an overall lower need of rotational energy and is therefore deemed the better crane. Keywords: Forest machines, hydraulics, efficiency<br>I världen idag existerar två mekaniserade skördartekniker inom skogsavverkningen, helträdsavverkning och kortvirkesavverkningen. Den första innebär att hela träd skördas och skotas ut till en uppläggningsplats medan man inom korttimmeravverkningen istället fäller träden med en skördare som sedan kvistar och till sist kapar trädet till önskad längd. Denna avverkning är numera 100 procent mekaniserad och effektivare avverkning är ständigt i blickfånget. Effektivare avverkning kan yttra sig i antalet fällda träd per timme men också i bränslekostnader. Dessa krav ställer i slutändan krav på skördarna och skotarnas prestanda. Ponsse Oyj är ett finskt skogsmaskinsföretag med fabrik i Vieremä som tillverkar både skördare och skotare. Till dessa maskiner tillverkar man även egna kranar. För skördare har man två olika designer, dels en bomkran och dels en parallellkran. Dessa båda krantyper har lika räckvidd men olika geometrier och vikt, vilket också innebär att masströgheterna skiljer dem åt. Syftet med detta examensarbete har varit att undersöka en av vardera krantypen, C2 från bomkrantypen och C22 från parallelltypen ur ett energieffektivitetshänseende. Detta har gjorts genom att mäta hydraulpumpflödet och kranarnas rotationsenergi. Mer specifikt har båda kranarna modellerats i Simulink med hydraulik och mekanik för att avgöra vilken av kranarna som är effektivast när kranspetsen har flyttats i en rörelse lika för båda kranarna. Kranspetsrörelsen simulerades med olika laster och för olika rörelser. Denna rörelse har varit i planet och för att jämföra kranarna vid vridning har kranspetsen placerats i olika positioner och masströgheten beräknats för vridning kring rotationsaxeln. För given rotationshastighet beräknades sedan vederbörande rotationsenergi för de olika positionerna. Simuleringarna resulterade i en fördel för parallellkranen vid korta sträckor och obelastad kran. För längre räckvid visade istället bomkranen bättre effektvärden. För rotation av kranarna kring dess rotationsaxel med kranspetsen i olika positioner visar parallellkranen C22 högre energivärden än bomkranen när kranspetsen är placerad fem meter från rotationsaxeln men för positioner längre ut, vid 9,9 respektive 10 meter påvisar C2 kranen kräva högre energi, om än i nivå med parallellkranen. Energieffektivast ur rotationshänseende är således bomkranen då den överlag behöver lägre energi eller i nivå med den andra. Nyckelord: Skogsmaskiner, hydraulik, effektivitet
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Cieslar, Filip. "Modely a simulace pochodů bezemisního kolového nakladače s elektrickým pohonem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-442865.
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This diploma thesis deals with the creation of models simulating the processes of an emission-free wheel loader, which was created by rebuilding the original version with a combustion engine. Part of the work is the methodical creation of models from the basic part of the machine to a simplified model of the overall machine, its functional verification and calibration based on available information’s and measurements. In this paper, selected parameters of the overall machine model are verified based on performed measurements, the suitability of selected components is verified, and the optimization and modification of the model is performed based on verification. The aim of the thesis is to present the simulation and verification procedure and its practical use in the development of an emission-free wheel loader with electric drive.
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Náplavová, Eva. "Kalibrace hydraulického modelu vodovodní sítě." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409704.
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This diploma thesis deals with calibration of hydraulic simulation models, especially with methods used for calibration and parameters that are modified during calibration. The literature review in the field of mathematical modeling, basic principles applied in hydraulic modeling and the current approach to calibration and data collection is done in theoretical part. In the practical part of the thesis, a hydraulic model of the group water supply system Horní Dunajovice is built and subsequently calibrated. The calibration is first performed manually for the normal operational status and then using a calibration software created for this purpose for a load case with high velocity.
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Howe, Edmund. "Hydraulic Assessment of Notched River Training Structures on a Portion of the Lower Mississippi River Using the Adaptive Hydraulics Model." Thesis, Mississippi State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10275634.
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<p> River training structures are widely used to create and maintain navigable waterways, to restore rivers and channels in a more stable condition, to promote environmental benefits, and to protect people and infrastructure from damages or floods. Few historical datasets on the changes and impacts in secondary waterbodies resulting from notched river training structures are available for the Lower Mississippi River. Access to the notched training structures on the Lower Mississippi River remains difficult and inhibits data collection for monitoring efforts. This increases the need for alternative methods such as numerical models for assessing the performance of the notched training structures. A quasi-three-dimensional Adaptive Hydraulics model was assembled and used to provide a hydraulic assessment of seven notched river training structures in the Lower Mississippi River. The hydraulic assessment of the notches included assessing the impacts to navigation, the long-term trends, and the potential for aquatic wildlife habitat diversity.</p><p>
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Pospíšil, Radek. "Tlumení energie proudu vodním skokem v prostoru rozšíření koryta." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409720.
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The diploma thesis is focused on the evaluation of the suppression of supercritical current energy in the area of the river bed extension. The hydraulic model was used to simulate current conditions for different variants of river bed arrangement. Individual variants were then evaluated according to the relevant criteria and compared with each other. Results can be applied in hydrotechnical practice based on model similarity.
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Kolenčíková, Jana. "Model teplárenské sítě." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417740.
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Subject of this thesis is district heating and heating network model design. Firstly, it de-scribes basic principles of heat supply and its elements. Secondly, computational model of heating network is created based on grid map of the network. The model contains proposed pipeline system and calculation of heat and pressure losses. Lastly, price map for heat con-sumption points, in dependence on heat losses, is presented.
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Petrula, Lubomír. "Hodnocení kontaminace podzemních vod v oblasti Letiště Přerov." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265335.
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The main goal of this work is to assess ground water contamination at the Přerov airport as a consequence to oil products leakage. For this purpose a flow and transport model was created. Another goal is to create and assess several variations of unfavorable scenarios in terms of water quality. The final goal is to create a set of recommendations for the entire area.
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Ashby, Robert Craig. "INVESTIGATION OF USAGE OF VELOCITY AND PRESSURE DATA WITHIN A WATER DISTRIBUTION LAB MODEL FOR CALIBRATING HYDRAULIC MODELS." UKnowledge, 2013. http://uknowledge.uky.edu/ce_etds/8.
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Water distribution modeling for hydraulics and water quality is an important tool for managing system performance of water utilities. An important component of a water distribution model is the calibration of a network model with field data in the real world system. The calibration effort requires a protocol or selection criteria for the location of field measurements that best support the calibration effort. A water distribution model was constructed at the University of Kentucky hydraulics lab for the purpose of investigating the performance of water distribution models. The lab model contains numerous hydraulic (pressure, flows) and water quality (concentrations) sensors for measuring system characteristics. This research work utilizes the lab model to compare hydraulic calibration using pressure heads from hydraulic data, velocities from water quality data, and combinations of both as the basis of calibration. It also presents an example of a small experimental system where velocity data as a basis for a calibration effort and pressure based data as a basis doesn’t converge to the same solution. The results of the research demonstrate the necessity of using both velocity & pressure data for hydraulic calibration to avoid compensating errors.
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Pařízková, Iva. "Matematický model teplárenské sítě." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241664.
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This thesis is focused on creating an iterative model for thermal and hydraulic calculation of heating net in Visual Basic of Application. Flowing medium considered is hot water. Although data for heating network in Brno are recorded in this model, its use for any other heating network is possible. This model allows also calculation of minimal temperature of the source and calculation of heat loss of every consumer. This is very useful when considering, if supplying some of the consumers with the heat from a local source would not be more effective. The second part of this text is aimed to evaluation of different ways how to reduce the heat loss in heat network for source Červený mlýn. Both current situation and possibilities for the future are considered.
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Mrázek, Jan. "Posouzení vybrané části vodovodní sítě." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2021. http://www.nusl.cz/ntk/nusl-433394.
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The aim of this thesis is to research the field of water distribution system monitoring and modeling such system. In the next section the thesis describes a part of the water distribution system which is located in Pardubice district, specifically south of town Přelouč. With knowledge from the done research a hydraulic model will be done. This model made in EPANET interface will be calibrated and verified using data, which was acquired by the administrator of the system VAK Pardubice a.s. Afterwards new pipelines will be added to simulate the future situation accordingly to the area plans of the cencerned towns. Furthermore another aim is to simulate the requirements made towards the water distribution system in the future in case all the areas in area plan will be completely used. This will result into creation of forward looking hydraulic model which will show possible weaknesses of the water distribution system. In case of any shortcomings, according measures will be designed for future use.
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Kapusta, Juraj. "Diagnostika stroje založena na modelech." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-442841.
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The main idea is focused on the diagnostics of a specific hydraulic system, i.e. sensing the physical quantities of the hydraulic circuit with a tank and a centrifugal pump driven by an asynchronous motor. It is a system of pipes connected to the pump, where due to its work it creates a water flow and a pressure increase. In practice, this issue is also addressed in the energy and nuclear industries. Primary circuits in some cases cannot be designed or modified to be able measure locally the pressure value. It is necessary to measure this quantity indirectly - from the motor currents. The main idea of the work is to diagnose the system by an indirect method - specifically to detect the state of the hydraulic circuit (pressure, flow) from the values that we are able to measure and detect damage in advance. In the second part of the thesis is the application of the parts of a specific hydraulic system in the simulation environment MATLAB Simulink. The model of the hydraulic circuit contains mathematical-physical relations that simulate the course of the mentioned experiment. The results of the simulation are compared with the results of the experiment. The model also investigates the simulation of a fault condition, when we supply pressure pulsations to the hydraulic circuit. It is these changes in the hydraulic part that affect the characteristics of the pump and the asynchronous motor, so we are able to diagnose this system.
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Flanagan, James P. A. "Formulation & Calibration of a Numerical model of the tidal hydraulics of McCormacks Bay." Thesis, University of Canterbury. School of Engineering, 1997. http://hdl.handle.net/10092/1101.
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The experimental investigation in this report was conducted both as indicator of the problems in McCormacks bay, and also as a base for the calibration of a numerical model of the hydraulic characteristics of the bay. There are some issues of public concern associated with the bay at the present time. These are related to dominant algae populations and their related problems, and the desire to preserve the existing bay as a healthy marine environment. Numerical models can be a useful tool to test various management options. A component of this study involved the calibration of a numerical model which described the response of the bay to tidal functions in the estuary. Calibration was achieved using data from measurements taken on the eighteenth of December 1996. The model was based specifically around the main central culvert running under the causeway. The model showed that an increase in the depth of this culvert would increase the range of water levels in the bay by up to 23%. This is significant and would increase the tidal exchange in the bay, thereby promoting circulation.
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Blase, Thomas. "Ein systemtechnischer Ansatz zur Modellierung von Hydraulik, Stofftransport und reaktionskinetischen Prozessen in Kläranlagen /." Hannover : Inst. für Strömungsmechanik und Elektronisches Rechnen im Bauwesen, 1995. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=007054569&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Wong, Ka-chung Colin, and 黃家聰. "Hydraulics of bottom rack chamber for supercritical flow diversion." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42664469.
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Gilè, Cristiano. "Realization of a dual clutch transmission hydraulic and thermal model for HIL applications." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16242/.
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Depleting oil resources and global warming has led to a continual search in the automotive field to find a cost-effective solution to develop more and more fuel efficient vehicles. In the last years the number of electric and hybrid vehicles have rapidly increase thanks to pollution standards and their high efficiency. It is possible to define three main categories, based mainly on the power of the electric motor and the capacity of the batteries. In "mild" hybrids, a small unit takes the place of the alternator and starter motor, and is connected to the main engine with a belt. When it slows down, it recharges a battery, while the energy flow is reversed, and the current motor "helps" the thermal one. The "full" hybrids have instead more powerful electric motors that are integrated with the rest of the vehicles : they are often part of the transmission. The "plug-ins" are "full" equipped with much larger batteries, which allow a range of tens of kilometers without using fuel; to be able to charge them to the maximum, however, it is necessary to connect them to the electric network through a cable. Otherwise, these cars behave like "full" hybrids: the accumulators are filled by the inertia of the vehicle when it slows down.
As a result of this, new concepts called hybrid dual clutch transmission (HDCT) have been developed. These new type of transmission are suitable for multiple hybridisation topologies, as the e-machine can be connected to the transmission by different methods in order to obtain a more efficient interaction of the internal combustion engine and the e-machine. Compared to an automatic transmission based on planetary gearsets or to continuous variable transmissions (CVT), further optimisation potentials can be achieved thanks to the flexible hybridisation concept.
This thesis aims to realize a model to calculate the heat generated by an hybrid dual clutch transmission in real-time without a great amount of computing power.
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Marjavaara, Daniel. "CFD driven optimization of hydraulic turbine draft tubes using surrogate models." Doctoral thesis, Luleå : Division of Fluid Mechanics, Luleå University of Technology, 2006. http://epubl.ltu.se/1402-1544/2006/41/.
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Friman, Jacob. "Skyfallskartering i Kumla : 2D-hydraulisk modellering och känslighetsanalys." Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-325123.
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Översvämningar till följd av intensiva nederbördstillfällen har de senaste åren ökat i antal och omfattning. Dessa händelser förväntas bli vanligare i framtiden och skapa fler översvämningar. Med anledning av detta är det intressant att undersöka hur översvämningar i framtiden breder ut sig och vilka vattennivåer som bildas med förväntad nederbörd. Att modellera översvämningar kräver data som i vissa fall kan vara både tidskrävande och omständig att införskaffa. Möjliga avgräsningar och antaganden i modellparametrar kan då vara intressanta att göra som fortfarande ger användbara resultat. En skyfallskartering har genomförts med 2D-hydraulisk modellering i Kumla med programvaran MIKE 21 Flow Model FM. De översvämningskartor som skapades användes för att identifiera områden i Kumla som riskerar att drabbas av höga vattennivåer till följd av skyfall motsvarande 100- och 200-årsregn. En stor osäkerhet vid modellering av översvämningar är att validera resultaten som fås fram. Ofta saknas information om tidigare översvämningar. De nederbördstillfällen som används är ofta så stora att det saknas data om liknande händelser tidigare. Vid översvämningsmodellering anväds data som beskriver olika typer av modellparametrar. Dessa kommer med ytterligare osäkerheter som kan göra valideringen problematisk. För att undersöka hur stor effekt olika modellparametrar har på resultatet genomfördes en känslighetsanalys där differenskartor skapades mellan undersökta scenarion och referenskartor. Skyfallskarteringen visade att stora delar i Kumla drabbas av översvämningar för både ett 100- och 200-årsregn. Området Kumlaby identifierades som känsligt och får höga vattennivåer. Detta beror mest troligt på omgivningens topografi och att Kumlaby underlagras av leror med låg infiltrationskapacitet. I känslighetsanalysen identifierades markens råhet och infiltrationskapacitet vara styrande parametrar för översvämningens utbredning och vattennivåer. Dessa påverkar främst hur höga vattenflöden som uppstår och översvämningens utbredningen och vattennivåer. Kunskap om dessa parametrar är viktigt för att undvika över- eller underskattning av en översvämning. Användningen av avrinningskoefficienter istället för markens råhet, infiltrationskapacitet och evaporation undersöktes. Differensen i översvämningens utbredning och vattennivåer blev stor i och utanför Kumla tätort. På mindre områden kan det vara mer lämpligt att använda en avrinningskoefficient när en mer detaljerad klassning kan göras av de markytor som finns. Ett scenario som undersöktes i känslighetsanalysen var installation av gröna tak på alla byggnader i Kumla. Simuleringarna som genomfördes visade att både utbredningen och vattennivåer minskade. Detta till följd av större lagringskapacitet och motstånd mot vattenflöden som kommer med gröna tak.<br>Urban floods caused by intense rainfall have occurred more frequently the last couple of years. These rainfall events are expected to become more common in the future and create more floods in urban areas. This makes it important to investigate the extent and water levels from urban floods in the future. In order to simulate floods, different types of data is needed. This data can be both time consuming and difficult to obtain. With this in mind, it is interesting to investigate possible simplifications and assumptions of model parameters. A cloud burst mapping was made with 2D hydraulic modelling in Kumla with the software MIKE 21 Flow Model FM. The flood maps created were used to identify areas in Kumla which have a higher risk of being subject to high water levels. One uncertainty while modelling urban floods is the process of validating the results. There is often a lack of data for the used rainfall events or information from previous floods in the area. In flood modelling data is used which describes different model parameters, these comes with additional uncertainties and can make the validation more difficult. A sensitivity analysis was made to be able to examine effects on the results from variations in model parameters. The cloud burst mapping showed that large parts of Kumla will be affected by water levels which goes up to 1 m. The area Kumlaby was identified as being sensitive for high water levels. This is due to placement of Kumlaby below higher ground which causes water to flow toward Kumlaby. The ground below is mostly made up of clay which has low infiltration capacity. In the sensitivity analysis the bed resistance and infiltration capacity were identified as governing parameters regarding the extent and water levels of urban floods. In order to avoid over- or underestimation of floods it is important to have knowledge about these parameters in the model area. The use of a runoff coefficient instead of bed resistance, infiltration and evaporation were examined. The difference of the resulting flood were large in the whole model area. In smaller areas a runoff coefficient could be used with better results when a more detailed description can be made of the surfaces in the area. A scenario where green roofs were assumed to have been installed on all buildings in Kumla were examined. The simulations showed that both the extent and water levels decreased. This due to the fact that green roofs have a capacity to store water and delay flows of water.
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Wong, John Kam-wing. "Three-dimensional multi-scale hydraulic fracturing simulation in heterogeneous material using Dual Lattice Model." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/270542.
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Hydraulic fracturing is a multi-physics multi-scale problem related to natural processes such as the formation of dikes. It also has wide engineering applications such as extraction of unconventional resources, enhanced geothermal energy and carbon capture and storage. Current simulators are highly simplified because of the assumption of homogeneous reservoir. Unconventional reservoirs are heterogeneous owing to the presence of natural fracture network. Because of high computational effort, three-dimensional multi-scale simulations are uncommon, in particular, modelling material as a heterogeneous medium. Lattice Element Method (LEM) is therefore proposed for multi-scale simulation of heterogeneous material. In LEM, material is discretised into cells and their interactions are modelled by lattices, hence a three-dimensional model is simplified to a network of one-dimensional lattice. Normal, shear and rotational springs are used to define the constitutive laws of a lattice. LEM enables desktop computers for simulation of a lattice model that consists of millions of lattices. From simulations, normal springs govern the macroscopic bulk deformation while shear springs govern the macroscopic distortion. There is fluctuation of stresses even under uniform loading which is one of the characteristics of a lattice model. The magnitude increases with the stiffness ratio of shear spring to normal spring. Fracturing process can be modelled by LEM by introducing a microscopic tensile strength and a microscopic shear strength to the lattice properties. The strength parameters can be related to fracture toughness with the length scales of cells. From simulations, the relationships between model parameters and macroscopic parameters that are measurable in experiments are identified. From the simulations of uni-axial tension tests, both the spring stiffness ratio and the applied heterogeneity govern the fracturing process. The heterogeneity increases the ductility at the expense of the reduction on the macroscopic strengths. Different stages of fracturing are identified which are characterised by the model heterogeneity. Heterogeneous models go through the stages of the spatially distributed microscrack formation, the growth of multiple fracture clusters to the dominant fracture propagation. For homogeneous models, one of the microcracks rapidly propagates and becomes a dominant fracture with the absence of intermediate stages. From the uni-axial compression test simulations, the peak compressive stress is reached at the onset of the microscopic shear crack formation. Ductility is governed by the stiffness reduction ratio of a lattice in closed fractured stage to its unfractured stage. A novel Dual Lattice Model (DLM) is proposed for hydraulic fracture simulation by coupling a solid lattice model with a fluid lattice model. From DLM simulations of hydraulic fracturing of the classical penny shape crack problem under hydrostatic condition, the heterogeneities from both the fracture asperity and the applied heterogeneity increase the apparent fracture toughness. A semi-analytical solution is derived to consider the effect of fluid viscosity in the elastic deformation regime. Two asymptotes are identified that gives steep pressure gradients near the injection point and near the fracture tip which are also identified in the DLM simulations. Simulations also show three evolving regimes on energy dissipation/transfer mechanisms: the viscosity dominant, the elastic deformation dominant and the mixture of elastic deformation and toughness.
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Choi, Chi Chi. "Coupled Hydrologic And Hydraulic Models And Applications." Thesis, University of Iowa, 2013. https://ir.uiowa.edu/etd/4955.
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Kapelan, Zoran. "Calibration of water distribution system hydraulic models." Thesis, University of Exeter, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370011.
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A number of mathematical models are used nowadays to describe behaviour of the reallife water distribution system (WDS). It is a well known fact that, to have any meaningful use, any WDS mathematical model must be calibrated first. Here, calibration is defined as process in which a number of WDS model parameters are adjusted until the model mimics behaviour of the real WDS as closely as possible. In this thesis, WDS mathematical models that are used to model water quantity aspect only are analysed. Three hydraulic models considered here are: (1) steady-state flow model, (2) quasi-steady flow (extended period simulation) model and (3) unsteady flow model. The calibration problem analysed here is formulated as a constrained optimisation problem of weighted least square type with the objective defined in a way that enables effective incorporation of prior information on calibration parameters. WDS calibration problem is then analysed in detail, including special issues of identifiability, uniqueness and stability of the problem solution. A list of diagnostic and other statistics and analysis is presented to improve existing calibration approaches by providing partial insight into the calibration process. Calibration of WDS hydraulic models is further improved by the development of new hybrid optimisation method. Being closely related to calibration, the problem of sampling design for calibration of WDS hydraulic models is also addressed here. First, sampling design is formulated as a constrained two-objective optimisation problem. Then, two novel models are developed to solve it. The first model is based on standard, single-objective Genetic Algorithms (SOGA). The second model is based on multi-objective Genetic Algorithms (MOGA). Finally, all novel methodologies presented here are verified successfully on multiple case studies that involve both artificial and real-life WDS. At the end, relevant conclusions are drawn and suggestions for further research work are made.
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Balas, Jan. "Hydraulické posouzení stokové sítě obce Lipůvka." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265284.
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Diploma thesis is focused on hydraulic assessment of Lipůvka´s sewer system, done by dynamic rainfall-runoff simulation model. Because of this fact, chapter about mathematical models is included. Commonly used programs to this actions are listed as well. Next part of the thesis describes monitoring campaign, which was done in Lipůvka and results are used to calibrate the simulation model. Hydraulic assessment of sewer system by this calibrated model was done.
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Hradilová, Iva. "Modelování hydraulické účinnosti vícekomorových septiků." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227222.
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The submitted diploma thesis is focused on finding optimal inside arrangement of multi-chamber septic tank using the conductive method. The diploma thesis brings detailed description and measuring results, including the testing of several different arrangements of the standard circular three chamber septic tank in the project TAČR with the working title "Anasep" and newly developed four-chamber septic tank with several innovative features. The results are then categorized according to own terminology for ease application in the practice. The described method may be a suitable alternative for other technically and economically less available methods. The method shows very clearly whether the inner space of the septic tank sufficient use its volume to the velocity field distribution which has a direct impact on the rate of sedimentation of suspended solids and therefore affect the life of the downstream filtration equipment. Measured data processing and graphical outputs were processed in the programme Minitab. Graphical display of all variants of septic tanks was carried out using SketchUp. Visualization of a septic tank in 2D and 3D space plane was solved in COMSOL Multiphysic with the application of CFD module. The conclusion is based on achievements discussed the applicability of the described method and it presented hydraulically efficient multi-chamber septic tank, which is currently copyrighted solution, developed by a team of solvers in the project ANASEP.
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Yang, Bo. "Elastohydrodynamic model of reciprocating hydraulic rod seals." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34747.
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Reciprocating rod seals are widely used in hydraulic systems to prevent the hydraulic fluid from leaking into and polluting the environment. In this research an elastohydrodynamic model of a generalized reciprocating hydraulic rod seal, including mixed lubrication and surface roughness, has been successfully developed. This model consists of coupled fluid mechanics, contact mechanics, thermal analysis and deformation analyses.
Such model is capable of predicting the key seal performance characteristics, especially net leakage and friction force. This allows evaluation of potential seal designs and serves as design tools. Also as this model has been developed, the basic physics of seal operation has been clarified, which stimulates the development of innovative seal concepts, such as seals with engineered sealing surfaces.
The results of this study indicate that in general, hydraulic rod seals operate in the mixed lubrication regime, although under certain conditions full film lubrication may occur over a portion of the sealing zone. The roughness of the seal surface and the rod speeds play important roles in determining whether or not a seal will leak. Cavitation during the outstroke and partial full film lubrication during the instroke tend to prevent net leakage. The behavior of a reciprocating hydraulic rod seal with a double lip or two seals in tandem arrangement can be very different from that of a similar seal with a single lip. For the double lip seal, the secondary lip can strongly affect the behavior of the primary lip by producing an elevated pressure in the interlip region. The same seal characteristics that promote effective sealing in a single lip seal and, in addition structural decoupling of multiple lips, are found to promote effective sealing in a multiple lip seal.
The model is validated through comparisons of model predictions with experimental measurements and observations by industry partners. The results have shown the predicted leakage and friction force for various seal and operation conditions are consistent with the measurements.
A seal with micro-pattern on the sealing surface also has been investigated. The results indicate that an elaborately designed pattern can improve the sealing characteristics of the seal, without significantly affecting the friction force.
In the end, the selection of the rod seal for a specific application using this analytical model is demonstrated. The best design can be picked up before a prototype being built.
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Van, Der Merwe Carel Wagener. "A peridynamic model for sleeved hydraulic fracture." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95993.
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Thesis (MEng)--Stellenbosch University, 2014.<br>ENGLISH ABSTRACT: Current numerical methods in the eld of hydraulic fracturing are based mainly on
continuum methods, such as the Finite Element Method (FEM) and the Boundary Element
Method (BEM). These methods are governed by Linear Elastic Fracture Mechanics
(LEFM) criteria, which su er from the inherent
aw of a non-physical stress representation
at the fracture tip. In response to this, a non-local method is proposed, namely
the peridynamic theory, to model sleeved hydraulic fracture. A 2D implicit quasi-static
ordinary state based peridynamic formulation is implemented on various benchmark
problems, to verify the ability to capture constitutive behaviour in a linear elastic solid,
as well as, the quanti cation of adverse e ects on the accuracy of the displacement solution,
due to the nature of the non-local theory. Benchmark tests consist of a plate in
tension, where convergence to the classical displacement solution, non-uniform re nement
and varying cell sizes are tested, as well as, a thick walled cylinder with internal
pressure, where three di erent loading techniques are tested. The most accurate loading
technique is applied to the sleeved fracture model, in order to simulate fracture initiation
and propagation. This model is then veri ed and validated by using the Rummel &
Winter hydraulic fracturing model and experimental results, respectively. Displacement
error minimisation methods are implemented and as a result, the displacement solutions
for a plate in tension converges to the analytical solution, while the thick walled cylinder
solutions su er from inaccuracies due to an applied load on an irregularly discretized
region. The fracture initiation test captures the fracture tip behaviour of the Rummel
& Winter model and the fracture propagation test show good correlation with experimental
results. This research shows that the peridynamic approach to sleeved hydraulic
fracture can yield a realistic representation of fracture initiation and propagation, however,
further research is needed in the area of a pressure load application on a solid using
the peridynamic approach.<br>AFRIKAANSE OPSOMMING: Huidige numeriese metodes in die veld van hidrouliese breking is hoofsaaklik gebaseer
op kontinuum metodes, soos die Eindige Element Metode (EEM) en die Rand Element
Metode (REM). Hierdie metodes word beheer deur Linie^ere Elastiese Breukmeganika
(LEB) kriteria, wat ly aan die inherente gebrek van 'n nie- siese voorstelling van die
spanning by die fraktuur punt. Om hierdie probleme aan te spreek, word 'n nie-lokale
metode voorgestel, naamlik die peridinamiese teorie, om gehulsde hidrouliese breking
te modelleer. 'n 2D implisiete kwasi-statiese ordin^ere toestand gebaseerde peridinamika
formulering word ge mplimenteer op verskeie norm probleme, om te veri eer of dit oor
die vermo e beskik om die konstitutiewe gedrag van 'n linie^ere elastiese soliede materiaal
te modeleer, asook die kwanti sering van nadelige e ekte op die verplasings oplossing as
gevolg van die natuur van die nie-lokale teorie. Normtoetse bestaan uit 'n plaat in trek
spanning, waar konvergensie na die klassieke verplasings oplossing, nie-uniforme verfyning
en vari^eerende sel groottes getoets word, asook 'n dikwandige silinder onder interne
druk, waar drie verskillende belasting aanwendingstegnieke getoets word. Die mees akkurate
belasting aanwendingstegniek word dan gebruik in die gehulsde hidrouliese breking
model, om fraktuur aanvangs en uitbreiding na te boots. Die model word dan geveri-
eer deur die Rummel & Winter hidrouliese breking model en eksperimentele resultate,
onderskeidelik. Fout minimering metodes word toegepas en as 'n resultaat, konvergeer
die verplasing oplossing vir die plaat na die analitiese oplossing, terwyl die oplossing
van die dikwandige silinder onakuraathede toon as gevolg van 'n toegepaste belasting
op 'n onre elmatig gediskretiseerde gebied. Die modellering van die fraktuur inisi ering
by die fraktuur punt, stem goed ooreen met die Rummel en Winter voorspelling en die
fraktuur uitbreiding stem goed ooreen met eksperimentele resultate. Hierdie navorsing
toon dat die peridinamiese benadering tot gehulsde hidrouliese breking wel die fraktuur
inisi ering en uitbreiding realisties kan modelleer, maar nog navorsing word wel benodig
in die area waar 'n druk belasting op 'n peridinamiese soliede model toegepas word.
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Wahler, Matthias, and Thomas Sendelbach. "Model based engineering for electro-hydraulic solutions." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71232.
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This paper will give an overview about the technological change in Industrial Hydraulics and the impact of the Digital Twin on the related new engineering processes and methods in order to overcome the challenges coming out of that technology change. Simulation models will more and more become a decisive factor for the engineering process. The Digital Twin will be a window of opportunity for innovations and a technology push for the engineering process and the products in the Industrial Hydraulics.
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Wood, Melissa. "Improving hydraulic model parameterization using SAR data." Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715776.
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Foust, Richard John. "Development of a hydraulic bone chamber implant to study in vivo bone repair and adaptation." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/17123.
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Albright, Lydia T. "Hydraulic Modeling of Floods in an Open Conduit Cave." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1596647829960682.
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Firoozfar, Ali Reza. "Rock scour in hydraulic laboratory analog scour models." Diss., University of Iowa, 2014. https://ir.uiowa.edu/etd/1456.
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Erosional processes of solid materials have been the focus of many researchers around the world. Erosion can commence within a wide range of material strengths depending on the amount of water-driven energy and material properties. Erosion could also occur due to Aeolian effects as well as chemical weathering but these forcings are not of the focus of this research. Instead, the focus here is on rock erosion in waterways and in particular downstream of dams.
Rock erosion mostly takes place at the downstream of dams where the water conveys through the spillbays from upstream to the downstream during an extreme event. This phenomenon threatens both the structural soundness of the dam with implications to the public safety. It usually occurs when the applied hydrodynamic forces (average and fluctuating) exceed the strength of the rock mass formation. Rock scour at the downstream of dams due to high velocity impinging jet is a complex and highly dynamic process. So a deeper understanding of the process is crucial to determine the rock scour rate and extent.
Hydraulic laboratory models have been employed to investigate hydraulic processes and proved to be reliable tools for testing soil/sediment erosion; however, the study of rock scour remains challenging. The prototype rock formation cannot be utilized in the laboratory models because the flowing water in the scaled model contains much less energy and exerts less forcing. On the other hand, the use of granular sediment (non-cohesive), as a standalone approach to mimic the rock formation is not a precise method, since it will most probably lead to inaccurate results.
The idea of using a mixture of granular and cohesive sediment is investigated here to adequately simulate the rock erosion process in the laboratory scaled models. The granular sediment represents the rock blocks while the cohesive additive is a binder to keep the granular sediment together.
The rock scour process can occur through four mechanisms; fracture failure, block removal, fatigue failure and abrasion. In this study, because the focus is on the hydrodynamic forcing effects on rock erosion, we assume that in the completely and intermittently jointed rock, erosion is mostly governed by fracture, block removal and fatigue failure. Abrasion is triggered by collisional effects and is not the focus here. So, we hypothesize that if the rock formation considered being pre-fractured, it can be simulated using a mixture of non-cohesive sediment with cohesive additive.
This method was utilized to assess the rock scour process at the downstream of the Priest Rapids Dam. The Priest Rapids Dam project was part of a series of projects that was conducted at IIHR-Hydroscience & Engineering at The University of Iowa and sponsored by the Public Utility District No. 2 of Grant County, Ephrata, Washington (GCPUD) to investigate juvenile salmonid migration at the Wanapum/Priest Rapids Development. It is a hydroelectric, concrete gravity, and mid-elevation dam owned and operated by Public Utility District No. 2 of Grant County, Washington (the "District").
To aid the District in their evaluation of fish passage, IIHR-Hydroscience & Engineering constructed comprehensive three-dimensional physical models of the forebay and tailrace of Priest Rapids Dam and a third model of spillbays 19-22 and powerhouse Unit 1 (sectional model).
As part of the last phase of the project, it was crucial to assess the effects of the newly designed fish bypass system on the downstream rock foundation scour. To investigate this process, the 1:64 Froude-based scale tailrace model of the dam was utilized. The mixture of gravel, bentonite clay, and water was employed to mimic the rock formation and simulate the bedrock scour process in the model. Series of preliminary experiments were conducted to find the optimum mixture of gravel, bentonite and water to accurately replicate an existing scour hole observed in the prototype tailrace. Two scenarios were considered. First, tests were conducted to estimate the scour potential downstream of the fish bypass, which is currently under construction. Second, the scour potential downstream of the dam was also assessed for the Probable Maximum Flood (PMF) with the fish bypass system running. Based on the model tests results and observations, the simulated bedrock (mixture of gravel and cohesive bentonite) was able to replicate the rock scour mechanisms, i.e. fracture process, block removal and fatigue observed in nature. During the fish bypass scour tests, it was observed that the erosion process occurs in the form of block removal and fatigue failure.
During the PMF scour test, instead, it was observed that the mixture is eroded in chunks of substrate. This process can be representative of fracture failure in rock which occurs when the induced pressure fluctuation exceeds the fracture strength or equivalently toughness of the rock. In the preliminary phase of this work it was recognized that a prerequisite for replicating the processes in the laboratory is the proper preparation of the mixture. There is limited information available in the literature about how much cohesive additive is required to simulate the erosional strength of the prototype rock formation.
For this reason, in this study the effort has been made to develop a method to simulate the rock formation for studying rock scour process in the laboratory analog scaled models. To simulate the bedrock formation, various combination of granular sediment (gravel), cohesive additive, and water were created and tested. Choosing an appropriate cohesive additive concentration is critical and nearly a balancing act. An appropriate cohesive additive concentration should be cohesive enough to bind the material and not too strong to be eroded by the flowing water in the scaled models. Moreover, its properties should not change over time. Various cohesive additives can be mentioned i.e. kaolin clay, bentonite clay, cement, grease, paraffin wax. Among all of them, bentonite clay was chosen as the appropriate cohesive additive due to its swelling characteristic. When bentonite is mixed with granular sediment, it is restricted by the non-cohesive sediment grains. The bentonite expands to fill the voids and forms a tough, leathery mineral mastic through which water cannot readily move.
In order to assess the erodibility of the mixture the Jet Erosion Test (JET) apparatus was used. The JET apparatus is a vertical, submerged, circular, turbulent impinging jet which is widely accepted and utilized to assess cohesive soil erosion through flow impingement. There are devices such as flumes which could be effectively used for bank erosion where the flow shear action is prevalent. In this study, it was sought important that the forcing replicated in the experiments was of the same nature (normal impinging forcing instead of shear forcing) as observed in the downstream end of a dam. For this reason, JET was chosen as it provided a larger range of stresses (ranging between 100-1000 Pa) comparing to the flume device. The apparatus was designed based on the device developed by Hanson and Hunt (2007) and built at the IIHR-Hydroscience & Engineering.
Various replicate samples were made with different combinations of gravel, sodium bentonite clay, and water. To determine the erosional strength of the samples (critical stress) they were tested using the JET apparatus. The critical stress was determined as the stress associated with zero eroded mass. The results revealed that the erosional strength of the simulated bedrock mixtures highly depends on the amount of adhesive component (bentonite clay). The mixtures with the higher percentage of bentonite clay are less susceptible to erosion. The erosion threshold plot - similar to Annandale's plot - for the simulated bedrock mixtures was developed.
Using the erosional strength of the simulated bedrock mixtures, a step-by-step systematic method was developed to determine the optimum combination of weakly cohesive substrate in order to simulate the strength of the prototype bedrock. The method is based on the Annandale's erodibility index method and requires information about the prototype bedrock strength (erodibility index). The method is explained in conjunction with the Priest Rapids Dam project example.
The old trial and error method to establish an optimum weakly cohesive substrate is costly and time consuming especially in the case of large scale laboratory models. Also, the applicability of the method would be questionable when there is not enough information or a past data set that can be used as a baseline (witness) test. The new method eliminates these problems and the optimum mixture can be established using the geological information of the prototype bedrock formation.
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Hampson, S. P. "Nonlinear model predictive control of a hydraulic actuator." Thesis, University of Canterbury. Mechanical Engineering, 1995. http://hdl.handle.net/10092/6032.
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The main objective of this thesis is the development and implementation of a nonlinear optimal controller for a hydraulic positioning system. The controller is able to respond rapidly as well as take care of the changing dynamics within the hydraulic system.
The necessary attributes for a hydraulic actuator controller are determined by analysing the problems generally associated with hydraulic drives and reviewing the control methods that have been applied in the past. It is concluded that while significant advancements have been made in disturbance rejection, little effort has been placed on the optimal, or minimum time specifications which are frequently demanded by positioning systems. It is also noted that high perfoffi1ance hydraulic drives are prone to cavitation and a controller must necessarily avoid this.
The design of a hydraulic test rig is discussed and a novel valve drive circuit that allows direct digital control is presented. The ability of the rig to demonstrate typical control problems is established by experimental testing. The purpose of the test rig is to aid in the modelling process and for controller testing.
Power Bond Graphs are used to model the experimental rig and a comparison between a nonlinear model and experimental data shows good correlation. A linear model is also considered and shown to be ineffective at representing the rig dynamics over a range of inputs. By formulating an idealised model, valuable insights into the dynamic characteristics are obtained and the directional dependent gain of single ended rams explained.
The performance capabilities of the hydraulic rig are benchmarked by calculating the minimum time response of the hydraulic system subject to constraints on the actuator pressures, load velocity and position. A number of test cases are examined.
The research objectives of high performance and flexible constraint handling make model predictive control (MPC) an ideal approach. Model predictive controllers have been successfully applied within the chemical process industry but their application to robotics is hindered by the excessive computational requirements of the algorithm. Furthermore they are typically linear and so in their present form unsuitable. By simplifying the optimisation procedure involved in the MPC algorithm an implementable, nonlinear version of the controller has been tested. The controller is able to constrain the values of pressure, velocity and position within prescribed boundaries, thus eliminating the need for extra hydraulic components. Moreover, the speed of response is comparable to the theoretical optimum.
The work reported in this thesis contributes to the field of hydraulic systems control as it presents a novel, nonlinear optimal controller for a hydraulic positioning system. The controller differs from others reported in the literature in that it allows for the plant nonlinearities and forces the system to operate within prescribed boundaries on the state variables. As will be shown this eliminates the need for extra hydraulic components.
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Chen, Jinduan. "Stochastic Demand-hydraulic Model of Water Distribution Systems." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1439301579.
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Tahir, Taha. "Model investigation into the hydraulic performance of mattress protected slopes of low head hydraulic structures." Thesis, University of Southampton, 1993. https://eprints.soton.ac.uk/414081/.
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The aim of this study was to provide some information about the hydraulic performance of mattresses protecting slopes of low head hydraulic structures. The flow resistance as well as stability of slope were investigated. The experimental programme was conducted in the Chilworth Hydraulics Laboratory, Department of Civil Engineering. Two models were constructed and tested. The inpermeable model (first) had a slope of 1:7 (V;H) with mattress dimensions of 320x350mm and a height of 40mm. The permeable model (second) was built with the same slope except that the mattresses were protecting a sand core. The flow resistance of the mattresses was studied which included Manning's roughness coefficient, Chezy's resistance factor and Darcy-Weisbach friction factor. Velocity distribution above the mattresses was evaluated and found well describing the flow. The stability of the mattresses and their ability to resist failure when exposed to higher discharges were also examined and found stable under the discharges tried. Detailed measurement of pressures were conducted in the permeable model in order to study their effects on the stability of the mattresses; such as; pressure distribution above the mattresses, uplift pressures and seepage forces. Shear stresses due to seepage forces were found very small and could be neglected. Comparison with the results of smooth board simulating a reinforced concrete structure, favours the mattresses as a means to control erosion and dissipate energy efficiently. Measures were suggested in terms of installation to reduce the drag and uplift forces. A design procedure for a slope protected by mattresses was set up and followed by a numerical example implementing the results obtained in this study.
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Matiaško, Dušan. "Modely a simulace pochodů bezemisního mini-exkavátoru s elektrickým pohonem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-442805.
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The diploma thesis dealt with a partial problem of conversion of the mini-excavator E19 by Bobcat with an internal combustion engine to emission-free propulsion. The main task was design and construction of electrical and hydraulic circuits focusing on the drive of a mini-excavator. The simulations verified the properties and behavior of the mini-excavator under different conditions and initial settings. The results were comfirmed by experimental measurements. The output of the simulations recommended adjustments to the values of individual parameters depending on the travel speed but also the efficiency of the entire machine.
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Trasky, Trevor Ryan. "Hydraulic model calibration for the Girdwood, Alaska water distribution system." Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/trasky/TraskyT0508.pdf.
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The possible EPA promulgation of regulations requiring flushing programs for water distribution systems to regulate water age is encouraging many utilities to develop a better understanding of their systems. This usually involves the development of a hydraulic model. For the hydraulic model to be of use it must be calibrated using collected field data. Few established guidelines exist for utilities to perform such data collection and calibration. There are many different types of data that can be collected using many different methods. There are also various model calibration methods that can be used. This study sought to develop an optimized sampling plan and calibration method for a small utility that defines the best practice for data type, location, quantity, and collection conditions. A large quantity of many data types were collected at various locations in the system. Different methods were used to calibrate the model with various data sets and the model accuracy was evaluated using a second independent data set. The effect of model input parameter accuracy and pipe grouping during calibration on overall accuracy was also investigated. Data type, location, quantity, and collection conditions had an impact on calibration accuracy. High headloss data from fire flow tests provided better calibrations than low loss data from static pressures. Carefully selected test locations resulted in more efficient calibration than evenly distributed test locations. There was found to be a point of diminishing returns when investigating the amount of data used in calibration versus calibration accuracy. Uncalibrated model input parameters such as elevations and pump characteristics also had a significant impact on model calibration accuracy.
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Kavli, Christian K. "Simple Model Representation of Underbalanced Drilling Hydraulics and Control." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26104.
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Oil reservoirs can be sensitive to unfamiliar fluids such as drilling fluids. In order to prevent fluids to enter the formations surrounding the well, the well pressure can be lowered below the reservoir pressure, called underbalanced drilling. This technique calls for injecting of gas into the mud to lower the pressure, with additional inflow of oil and gas to the well as a result. This thesis evaluates current modelling of two-phase flow related to underbalanced drilling, and possible simplifications. Through investigation of simulation data, the current modelling based on first principles, is considered too complex compared to data of the key dynamics. To simplify the modelling, a black box system identification approach is used. By identifying solely from simulation data, low order models with good fit to validation data are obtained. Through testing, the models' validity are tested, and it is concluded that a number of simple models will be needed to represent the whole system given by the simulator. Models with specific orders are tested at different set points, and one model order produces good accuracy at all the operating points tested. This model is likely to be able to accurately represent the whole system with updated parameters.The accuracy of the simple models identified reveals simple system dynamics, and a PI controller is considered to be sufficient. The models are being used to tune the controller, and the controller perform great on set point changes. In addition, the controller is tested with an emulated connection, with satisfactory performance.
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De, Schaetzen Werner. "Optimal calibration and sampling design for hydraulic network models." Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322278.
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ESCOBAR, RENATO GUTIÉRREZ. "INVESTIGATION OF HYDRAULIC FRACTURING THROUGH ANALYTICAL AND NUMERICAL MODELS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=28072@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO<br>COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR<br>PROGRAMA DE EXCELENCIA ACADEMICA<br>O processo de fraturamento hidráulico tem sido amplamente usado para aumentar o volume de petróleo e gás extraído na indústria petroleira. Durante a injeção de fluido, uma região determinada do reservatório é fraturada com a finalidade de aumentar a permeabilidade do meio poroso, de tal forma que o fluxo do fluido desde o reservatório para o poço seja favorecido notoriamente. Porém, este processo pode ocasionar danos ambientais tais como contaminação de aguas subterrâneas, vazamentos de gás, fraturas indesejadas nas camadas capeadoras pela injeção de agua e atividade sísmica fazendo primordial um estudo rigoroso do fraturamento hidráulico com a finalidade de reduzir os riscos potenciais associados a esta operação. Umas das metodologias usadas para projetar o fraturamento hidráulico é a simulação computacional. É possível determinar o volume injetado e a potência da bomba de injeção necessária para obter a geometria de fratura (comprimento, abertura e altura) desejada. A modelagem numérica através de elementos coesivos acoplados do processo de fraturamento hidráulico pode ser efetuada considerando o processo transiente ou permanente, tendo geometrias da fratura e curvas de injeção diferentes. Neste trabalho foi simulado numericamente o modelo KGD nos regimes de fluxo transiente e permanente para dois casos de estudo, (1) injeção numa única camada e (2) injeção em três camadas com contraste de tensões e poropressões entre elas. O estudo numérico foi desenvolvido usando o método dos elementos finitos com modelo de zona coesiva no software Abaqus o qual foi comparado com as soluções analíticas do KGD no regime dominado pela rigidez (Vértice-K) para uma camada e de Simonson e Fung para três camadas.<br>The hydraulic fracturing process has been widely used to improve oil and gas recovery in the petroleum industry. During the fluid injection, the desired section of rock formation is fractured in order to increase the permeability of the medium that can facilitate the flow of oil to a producing well. However, this process can lead to potential environmental risks such as seismic activity, unwanted fractures in cap layers by water injection, water contamination and gas leakage making primordial to develop a rigorous study in order to reduce this environmental risks associated to hydraulic fracturing. One of the studies developed to design the hydraulic fracturing is computational simulation to determine the fluid volume and hydraulic horsepower required in order to produce the wanted fracture geometry (length, opening and height). The numerical modelling of fracturing process by using fully coupled cohesive element hydraulic can be carried out considering either a steady state or a transient analysis, which modify the fracture geometry and injection pressure. In this work, the KGD model is simulated in transient and steady analysis for two cases: (1) injection in a single layer formation and (2) injection in tri-layered formation with stress and porepressure contrast between them. The numerical simulation of a hydraulic fracturing is carried out using the finite element method with the zone cohesive model in Abaqus whose results are compared with analytical solutions of toughness-dominated propagation regime for the one layer formation model and Simonson and Fung analytical solutions for tri-layered formations model.
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Wan, Frank Lup Ki. "Genetic algorithms, their applications and models in nonlinear systems identification." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30107.
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The Genetic Algorithm was used to estimate the hydraulic compliance of the hydraulic system on the UBC teleoperated heavy duty excavator. Using real recorded and simulation data from the excavator, the Genetic Algorithm has successfully identified the compliance of single link and multi-link hydraulic system of the excavator.
A Parallel GA ( PGA ) was implemented with 16 T800 Transputers. It achieved a speedup factor of 12 over a traditional GA. With such a high speedup factor, real-time monitoring of hydraulic compliance and other hydraulic parameters is becoming possible.
New mechanisms such as the distributed fitness function, the active error analysis were used to enhance the performance of a PGA. A PGA which incorporated these mechanisms actually outperformed a traditional GA in key areas such as variance of the estimated parameter and parameter tracking ability.
Finally, a physical model that explains the fundamental properties of GAs was introduced. The physical model ( a hypercube ) not only provides an excellent explanation of GAs searching power, but also gives insight to GAs users ways to improve and to predict the performance of GAs in most applications.<br>Applied Science, Faculty of<br>Electrical and Computer Engineering, Department of<br>Graduate
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Voldán, Karel. "Studie sanace stokové sítě vybrané části urbanizovaného celku." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372014.
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The aim of the diploma thesis was the elaboration of a study of the rehabilitation of the sewerage network in the part of the town of Znojmo. The work is conceived in the form of accompanying and technical reports. The accompanying report contains a brief description of the interest site, basic information about the sewerage system operator and land data. The technical report contains a description of the individual segments of the sewer network, supplemented by photo documentation of the selected faults located on the selected sections. In addition, the evaluation of the structural state of the sub-sections is carried out here. The following subchapter draws up two hydraulic models and their modifications after the recovery of the sewer system. Another part of the technical report describes possible options for remediation technologies. The last part deals with the conclusions and recommendations for the sewer network operator including a briefly outlined economic page in the selection of remediation technology.
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Kayani, Omer Khaleeq, and Muhammad Sohaib. "Generic Simulation Model Development of Hydraulic Axial Piston Machines." Thesis, Linköpings universitet, Fluida och mekatroniska system, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-76575.
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This master thesis presents a novel methodology for the development of simulation models for hydraulic pumps and motors. In this work, a generic simulation model capable of representing multiple axial piston machines is presented, implemented and validated. Validation of the developed generic simulation model is done by comparing the results from the simulation model with experimental measurements. The development of the generic model is done using AMESim. Today simulation models are an integral part of any development process concerning hydraulic machines. An improved methodology for developing these simulation models will affect both the development cost and time in a positive manner. Traditionally, specific simulation models dedicated to a certain pump or motor are created. This implies that a complete rethinking of the model structure has to be done when modeling a new pump or motor. Therefore when dealing with a large number of pumps and motors, this traditional way of model development could lead to large development time and cost. This thesis work presents a unique way of simulation model development where a single model could represent multiple pumps and motors resulting in lower development time and cost. An automated routine for simulation model creation is developed and implemented. This routine uses the generic simulation model as a template to automatically create simulation models requested by the user. For this purpose a user interface has been created through the use of Visual Basic scripting. This interface communicates with the generic simulation model allowing the user to either change it parametrically or completely transform it into another pump or motor. To determine the level of accuracy offered by the generic simulation model, simulation results are compared with experimental data. Moreover, an optimization routine to automatically fine tune the simulation model is also presented.
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Lopez, Sabater Carlos Joaquin. "An empirical model of hydraulic roughness for overland flow." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/280353.
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This research has developed a method for estimating hydraulic roughness coefficients for overland flow models in a dynamic approach, to more effectively simulate runoff on natural, agricultural and urban slopes. The hydraulic roughness coefficients are then generated with a series of neural networks. First, a laboratory experiment was designed to explore the effects of soil microtopography, slope and Reynolds number on the magnitude of Darcy-Weisbach, Manning and Chezy roughness coefficients. It was found that three parameters were necessary to describe the soil surface microtopography. Neural networks developed in a preliminary phase were able to reproduce the roughness coefficients obtained in the laboratory experiment by using five predictor variables: bed slope, Reynolds number, and the three parameters used to describe the microtopography. However, these networks failed to generate roughness coefficients for different input variables (generalization). Second, more complex algorithms were developed as combinations of neural networks in parallel. The algorithm output, the sought hydraulic roughness estimate, was estimated with the arithmetic average of the individual network outputs. Results presented in this study demonstrate that combining multiple neural networks reduced the prediction error and improved on the generalization ability of the neural networks. It was also observed that the estimate accuracy was influenced by the characteristics of the dataset, and especially by the relationship between the roughness coefficient and Reynolds numbers. Finally, a field experiment was performed to explore the applicability of the algorithms. A numerical model based on the 1-D diffusion approximation to the Saint Venant equations was constructed, and two surface irrigations were performed to collect data to test the model estimates. The model was used under two scenarios: (1) with constant hydraulic roughness coefficients, and (2) using variable hydraulic roughness predicted with the algorithm. Discharge at the end of the plot and irrigation front advance estimated using both models matched the observations well. However, when using a variable hydraulic roughness, the front was initially delayed until there was a sufficient surface storage to push it forward. The methodology described in this research should be useful for 2-D overland flow models applied to natural slopes with unsteady rainfall.
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Howarth, D. A. "The hydraulic performance of scale model storm sewer junctions." Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355907.
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Almeida, Fernando Gomes de. "Model reference adaptive control of two axes hydraulic manipulator." Thesis, University of Bath, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334573.
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Blank, Matthew David. "Advanced Studies of fish passage through culverts 1-D and 3-D hydraulic modeling of velocity, fish energy expenditure, and a new barrier assessment method /." Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/blank/BlankM0508.pdf.
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Fish passage through culverts is an important component of road and stream crossing design. Although no comprehensive inventory of the number of culverts on fishbearing streams in the United States is available, there is an estimated 1.4 million streamroad crossings. The most common physical characteristics that create barriers to fish passage include excessive water velocity, insufficient water depth and large outlet drop heights. Over the past decade, interest in the effect culvert barriers have on aquatic systems has grown; accordingly, various passage assessment techniques have been used to determine whether a structure is a barrier and to what degree (its “barrierityâ€). Recent research has shown that determining the barrierity of a culvert is not trivial, and that different methods are often not congruent in their classification of “barrierityâ€. The purpose of this research was to investigate the effect of velocity on fish passage in great detail by: testing the use of computational fluid dynamics (CFD) for estimating the 3-D velocity field through a culvert; quantifying velocity diversity through culverts for a range of flows; characterizing the energy expenditure paths through a culvert and identifying the passageways Yellowstone cutthroat trout used to successfully negotiate passage; and developing and testing a new barrier assessment method. The research was done, in part, by studying fish passage through culverts in Mulherin Creek, an important spawning tributary for Yellowstone cutthrout trout migrating from the Yellowstone River. Comparisons between predicted and observed velocities show 86% and 82% of variation in the observed velocity data were explained by the CFD model, for flow rates of 1.44 m3/s and 0.87 m3/s, respectively. The diverse velocity field through the culvert barrel created a range of energy expenditure paths through the entire culvert length. Fish movement observations showed successful passage only for trout seeking and using the minimum energy path created, in part, by the skew between the upstream channel and the culvert. This research investigated a new hydraulic approach to assessing barriers that uses the 3-D velocity field. Comparisons between estimated passage and measured passage show the 3-D method most accurately indicated passability compared to a 1-D method.