Dissertations / Theses on the topic 'Potential flow'
To see the other types of publications on this topic, follow the link: Potential flow.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Potential flow.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Dumancic, Dominik. "Flow batteries : Status and potential." Thesis, Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-12975.
Full textAbstract:
New ideas and solutions are necessary to face challenges in the electricity industry. The application of electricity storage systems (ESS) can improve the quality and stability of the existing electricity network. ESS can be used for peak shaving, instead of installing new generation or transmission units, renewable energy time-shift and many other services. There are few ESS technologies existing today: mechanical, electrical and electrochemical storage systems. Flow batteries are electrochemical storage systems which use electrolyte that is stored in a tank separated from the battery cell. Electrochemistry is very important to understand how a flow battery functions and how it stores electric energy. The functioning of a flow battery is based on reduction and oxidation reactions in the cell. To estimate the voltage of a cell the Nernst equation is used. It tells how the half-cell potential changes depending on the change of concentration of a substance involved in an oxidation or reduction reaction. The first flow battery was invented in the 1880’s, but was forgotten for a long time. Further development was revived in the 1950’s and 1970’s. A flow battery consists of two parallel electrodes separated by an ion exchange membrane, forming two half-cells. The electro-active materials are stored externally in an electrolyte and are introduced into the device only during operation. The vanadium redox battery (VRB) is based on the four possible oxidation states of vanadium and has a standard potential of 1.23 V. Full ionic equations of the VRB include protons, sulfuric acid and the corresponding salts. The capital cost of a VRB is approximately 426 $/kW and 100 $/kWh. Other flow batteries are polysulfide-bromine, zinc bromine, vanadium-bromine, iron-chromium, zinc-cerium, uranium, neptunium and soluble lead-acid redox flow batteries. Flow batteries have long cycle life and quick response times, but are complicated in comparison with other batteries.Nya idéer och lösningar är nödvändiga för att möta utmaningarna i elbranschen. Användningen av elektriskt lagringssystem (ESS) kan förbättra kvalitén och stabiliteten av det nuvarande elnätet. ESS kan användas till toppbelastningsutjämning, istället för att installera nya produktions eller kraft överförnings enheter, förnybar energi tidsförskjutning och många andra tjänster. I dagsläget finns det få olika ESS: Mekaniska, elektriska och elektrokemiska lagringssystem. Flödesbatterier tillhör kategorin elektrokemiska lagringssystem som använder sig utav elektrolyt som är lagrad i en tank separerad från battericellen. För att kunna förstå hur flödesbatteriernas funktioner och på vilket sätt som dem lagrar elektriskt energi är det viktigt att kunna elektrokemi. Flödesbatteriernas funktion är baserad på reduktions och oxidations reaktioner i cellen. Nernsts ekvation används för att kunna uppskatta voltantalet i en cell. Nernsts ekvation säger hur halvcell potentialen ändras beroende av ändringen av koncentrationen av ämnet involverat i oxidations eller reduktions reaktionen. Det första flödesbatteriet uppfanns 1880-talet, men blev bortglömt under en lång tid. Vidare utveckling förnyades under 1950 och 1970-talet. Ett flödesbatteri består utav två parallella elektroder som är separerade utav ett jonbytes membran vilket formar två halvceller. Dem elektroaktiva materialen är lagrade externt i elektrolyt och är införs bara i anordningen under användning. Vanadium redox batteriet (VRB) är baserat på dem fyra möjliga oxidations tillstånden av vanadium och har en standard potential på 1.23 V. Fullt joniska ekvationer av VRB inkluderar protoner, svavelsyra och deras motsvarande salter. Kapitalkostnaden av ett VRB är ungefär 426 $/kW och 100 $/kWh. Det finna andra flödesbatterier som är polysulfide-brom, zink-brom, vanadium-brom, järn-krom, uran, neptunium och löslig blysyre redox flödesbatterier. Flödesbatterier har en lång omloppstid samt en snabb svarstid men är komplicerade jämfört med andra batterier.
2
Yu, Wenyuan. "Development of a Fully Vectorized Potential Flow Solver." Thesis, KTH, Mekanik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-214950.
Full textAbstract:
Centered finite difference is the basic method in this paper for spatial discretization. In general, except the schemes that will be used adjacent tothe boundary points, centered finite difference schemes will be used on the main mesh points. Depending on the requirement of order of accuracy and optimization, different multi-point stencil schemes will be built in Matlab in the form of matrix. As a result, solving PDEs is actually operating matrices in Matlab. Standard schemes and optimized schemeswill be tested with 1D linear convection equation before applying them to the solvers. In 2D-pulse case, the rectangular domain will be transformed into a wavy domain and as a result Jacobian transformation method will betested. Results from different schemes will be compared with the analytical solution in two dimensional pulse case.
3
Hasson, Ali Thuriya A. Razzak. "A flow cell to study formation potential of pulps." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ29377.pdf.
Full text
4
Zhang, Jiazuo. "Self-potential during multiphase flow in complex porous media." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/48479.
Full textAbstract:
The rock pore space in many subsurface settings is saturated with water and one or more immiscible fluid phases; examples include non-aqueous-phase liquids (NAPLs) in contaminated aquifers, supercritical CO2 during sequestration in deep saline aquifers, the vadose zone, and hydrocarbon reservoirs. Self-potential (SP) methods have been proposed to monitor multiphase flow in such settings. However, to properly interpret and model these data requires an understanding of the saturation dependence of the streaming potential. This study presents a methodology to determine the saturation dependence of the streaming potential coupling coefficient and streaming current charge density in unsteady-state drainage and imbibition experiments and applies the method to published experimental data. Unsteady-state experiments do not yield representative values of coupling coefficient and streaming current density (or other transport properties such as relative permeability and electrical conductivity) at partial saturation because water saturation within the sample is not uniform. An interpretation method is required to determine the saturation dependence of coupling coefficient and streaming current density within a representative elementary volume with uniform saturation. The method makes no assumptions about the pore-space geometry. We also applied pore network models that can capture the distribution of fluids and electrical charge in real complex porous media to investigate and quantify streaming potential signals during multiphase flow at the pore level. The network modelling results were tested against the interpreted data and experimental data of Estaillades carbonate and St. Bees sandstone, which provided reliable pore-scale explanations of the experimental observations. The results presented here can be used to help interpret SP measurements obtained in partially-saturated subsurface settings.
5
Capanna, Roberto. "Modelling of fluid structure interaction by potential flow theory in a pwr under seismic excitation." Thesis, Ecole centrale de Marseille, 2018. http://www.theses.fr/2018ECDM0013/document.
Full textAbstract:
Une modélisation efficace et une connaissance précise du comportement mécanique du cœur du réacteur sont nécessaires pour estimer les effets de l'excitation sismique sur une centrale nucléaire. La présence d'un écoulement d'eau (dans les REP) engendre des phénomènes d'interaction fluide structure. La modélisation des interactions fluide structure sur les assemblages combustible revêt donc une importance fondamentale pour la sécurité des réacteurs nucléaires. L’objectif principal du projet de thèse présenté dans ce document est d’étudier les interactions fluide structure afin de mieux comprendre les phénomènes impliqués. La modélisation et l'approche expérimentale sont considérées. Un nouveau modèle linéaire simplifié pour les interactions fluide structure est développé en utilisant la théorie de l'écoulement potentiel pour la modélisation des forces fluide, tandis que le modèle de poutre d'Euler-Bernoulli est utilisé pour la partie structurelle. Le modèle est d'abord développé pour un seul cylindre et il est validé avec des ouvrages de référence dans la littérature. Les effets de la taille de confinement et du nombre d'onde sont examinés. Le modèle d'écoulement potentiel développé pour un seul cylindre est ainsi étendu à une géométrie multicylindre. La démarche expérimentale est donc nécessaire pour valider le modèle développé. Une nouvelle installation expérimentale, ICARE, a été conçue pour étudier les phénomènes d’interaction fluide structure sur des assemblages combustible à demi-échelle. Dans ce document, les résultats fournis par les mesures de déplacement et de LDV sont largement analysés. Le comportement dynamique de l'assemblage combustible et les effets de couplage sont étudiés. Les calculs sont comparés aux résultats expérimentaux afin de valider le modèle et d’en analyser ses limites. Le modèle est en accord avec les résultats expérimentaux concernant l'effet de masse ajouté. De plus, le modèle prédit qualitativement les effets des couplages dans différentes directions. Par contre, le modèle d'écoulement potentiel ne permet pas de prédire des effets d'amortissement ajouté, principalement dus aux forces visqueuses. Enfin, dans ce document, une autre application du modèle développé est décrite. Le modèle est utilisé afin de simuler des expériences réalisées sur une maquette d'assemblage combustible dans l'installation expérimentale installée à l'Université George Washington (GWU). Le modèle est capable de prédire et de fournir une interprétation valide de la perturbation du débit d'eau due au mouvement de l'ensemble excité. La thèse se termine par des perspectives d'amélioration du modèle, en intégrant des termes visqueux dans les équations. L'analyse des données de vélocimétrie par image de particules (PIV) recueillies au cours des campagnes expérimentales ICARE doit être poursuivieEfficient modelling and accurate knowledge of the mechanical behaviour of the reactorcore are needed to estimate the effects of seismic excitation on a nuclear power plant. Thepresence of cooling water flow (in PWRs) gives rise to fluid structure interaction phenomena.Modelling of fluid structure interactions on fuel assemblies is thus of fundamentalimportance in order to assure the safety of nuclear reactors. The main objective of thePhD project which is presented in this document is to investigate fluid structure interactionsin order to have a better understanding of the involved phenomena. Both modellingand experimental approach are considered. A new simplified linear model for fluid structureinteractions is developed by using the potential flow theory for fluid force modellingwhile the Euler-Bernoulli beam model is used for the structural part. The model, is firstdeveloped for a single cylinder and it is validated with reference works in literature. Theeffects of the confinement size and of the wavenumber are investigated. The potential flowmodel developed for a single cylinder, is thus extended to a multi cylinders geometry. Theexperimental approach is thus needed in order to validate the developed model. A newexperimental facility, ICARE, is designed in order to investigate fluid structure interactionphenomena on half scale fuel assemblies. In this document, the results provided bydisplacement and LDV measurements are widely analysed. The dynamical behaviour ofthe fuel assembly and coupling effects are investigated. Calculations are compared to theexperimental results in order to validate the model and to analyse its limits. The model isin agreement with experimental results regarding the added mass effect. In addition, themodel qualitatively predicts couplings effects on different directions. As a drawback, thepotential flow model cannot predict added damping effects, which are mainly due to viscousforces. Finally in this document another application of the developed model is described.The model is used in order to simulate experiments performed on a surrogate fuel assemblyin the experimental facility installed at George Washington University (GWU). The modelis able to predict and to provide a valid interpretation for the water flow perturbation dueto the motion of the excited assembly. The thesis concludes with perspectives for furtherimprovements of the model, by integrating viscous terms in the equations. Work needs tobe carried out on the analysis of Particle Image Velocimetry (PIV) data collected duringICARE experimental campaigns
6
Yaramadi, Dehnavi Pouya. "Global cycle of gallium production, use and potential recycling." Thesis, KTH, Mark- och vattenteknik (flyttat 20130630), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171838.
Full textAbstract:
Life cycle analysis is an appropriate way to clear obscure facts about an element. Gallium is a critical element which is used in many technologies these days and therefore quantification of main global cycles of gallium, production, consumption and end of life products, also investigation about recycled gallium content and potential recycling possibilities are investigated in this paper. First a qualitative substance flow for gallium is designed similar to other metal cycles with regards to exclusive characteristics of gallium flows itself. USGS and World Mining Data are mainly used to get information about gallium production, main gallium consumptions and end of life products. Subsequently a quantitative model in STAN should unlock many uncertainties. Substance flow analysis and material flow analysis give a better understanding of unknown gallium flows with their uncertainties and meanwhile major applications, concentration of gallium in different products, waste flows, landfills and present recycling technologies are detailed. Consequently STAN model asserts that main gallium flows are primary gallium production and refined gallium production in production process, Integrated Circuit board fabrication, Light Emitting Diodes, Photovoltaic and recycled new scrap flow in manufacturing process. A significant amount of gallium is collected as stock in consumption process. Also current gallium recycling facilities are limited as recycling is not economically justified. Moreover main part of recycled gallium content is collected from new scrap which is formed through manufacturing process. Finally gallium consumption in Photovoltaic and Light Emitting Diodes industry increases rapidly and sustainability demand cost efficient methods for gallium recycling from solar cells, diodes and other end of life products.
7
Belyadi, Fatemeh. "Determining low permeability formation properties from absolute open flow potential." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4879.
Full textAbstract:
Thesis (M.S.)--West Virginia University, 2006.Title from document title page. Document formatted into pages; contains viii, 63 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 36-42).
8
Chan, Johnson Lap-Kay. "Numerical procedure for potential flow problems with a free surface." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/28637.
Full textAbstract:
A numerical procedure based upon a boundary integral method for gravity wave making problems is studied in the time domain. The free-surface boundary conditions are combined and expressed in a Lagrangian notation to follow the free-surface particle's motion in time. The corresponding material derivative term is approximated by a finite difference expression, and the velocity terms are extrapolated in time for the completion of the formulations. The fluid-body intersection position at the free surface is predicted by an interpolation function that requires information from both the free surface and the submerged surface conditions. Solutions corresponding to a linear free-surface condition and to a non-linear free-surface condition are obtained at small time increment values. Numerical modelling of surface wave problems is studied in two dimensions and in three dimensions. Comparisons are made to linear analytical solutions as well as to published experimental results. Good agreement between the numerical solutions and measured values is found. For the modelling of a three dimensional wave diffraction problem, results at high wave amplitude are restricted because of the use of quadrilateral elements. The near cylinder region of the free surface is not considered to be well represented because of the coarse element size. Wave forces calculated on the vertical cylinder are found to be affected by the modelled tank length. When the simulated wave length is comparable to the wave tank's dimension, numerical results are found to be less than the experimental measurements. However, when the wave length is shorter than the tank's length, solutions are obtained with very good precision.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
9
Liani, Evandro. "Potential Flow Based Aerodynamic and Aeroelastic Analysis of flapping Wings." Thesis, Cranfield University, 2008. http://hdl.handle.net/1826/3210.
Full textAbstract:
The motivation for this research is the importance that the modeling of aerodynamics and aeroelasticity of flapping wings has had in the last decade. The development of flapping wings Micro Air Vehicles (MAV) has captured a huge interest in the recent past, due to the several disciplines involved in the subject. In this dissertation the attention is focused on the flow and its interactions with the structure.
Even though experiments have had a fundamental role in the explanation of the aerodynamics around a flapping wing, it is widely accepted that a key aspect in the development of future flapping wings MAVs is the modeling. The aim of the project is to investigate different techniques for the development of a numerical framework used in the prediction of the unsteady aerodynamic forces on flapping wings.
The understanding of the phenomena occurring on flapping wings is attempted first with very basic models. The research is carried out based on potential flow assumptions: the flow in initially treated as irrotational and inviscid. Although the assumptions are very strong, it is shown that the mechanisms of lift and thrust production can be described, together with the convection of the wake behind the wing. The limitation of potential flow models is the incapacity to describe flows that are separated over a large portion of the wing. The modeling of this issue is particularly important for flapping wings, where the separation is exploited in order tin increase the forces produced.
The development of a Vortex Particle Method (VPM) is attempted, with wake elements released at each time step from all the panels of the airfoil. The advantage of Vortex Particle Methods over panel methods is that they represent more realistically the flow around the wing. The drawback is the greater complexity and longer running times.
Aeroelasticity is discussed as well, as it is believed that the wing flexibility can enhance the performance of flapping wings. The thesis investigates the stability and response of an airfoil connected to a rotational and a linear spring at its elastic axis. Even though the structural model is very simple, it is shown that there might be advantages introducing a certain level of flexibility in the system.
The framework built in this project is not aimed at giving an accurate representation of the forces produced by flapping wings. A methodology that allows to avoid CFD computations is deemed fundamental in the design phase of an aerial vehicle. The final goal of this project is the development of meshless techniques for the aerodynamic analysis of unsteady flows. An essential point that needs deep insight is their inaccuracy compared to CFD. Therefore considerations about the lack of accuracy and ways to improve it are made in order to show that there is a real advantage in the sue of grid-free methods. The results of the analysis are compared with other results found in the literature. In particular, experimental results are considered where possible, otherwise numerical computation shave been taken into account. The first part of the code has been developed in FORTRAN, due to its running time efficiency, while the second part has been developed in C++, because of its ability to handle more complex data structures.
10
Hattersley, Nicola. "The potential of a seismic flow meter for mountain strams." Thesis, Bangor University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502744.
Full text
11
Dodworth, Kieran. "The application of potential flow theory to damaged hull dynamics." Thesis, University of Strathclyde, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366890.
Full text
12
Shi, Jun. "Finite element analysis of two dimensional unsteady incompressible potential flow." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46548.
Full text
13
Kakouei, Karan [Verfasser]. "Predicting potential ecological effects of flow alterations using quantitative flow preferences of stream macroinvertebrates / Karan Kakouei." Berlin : Freie Universität Berlin, 2018. http://d-nb.info/117663450X/34.
Full text
14
Harvey-Fros, Christopher Simon Francis. "The local potential approximation of the renormalization group." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285624.
Full text
15
Ayhan, Aytunc. "Online Critical Game Flow And Role Assignment Based On Potential Fields." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605708/index.pdf.
Full textAbstract:
This thesis describes the critical game flow and dynamic role assignment based on potential fields in robot soccer game and actions taken depending on role assignment. Role assignment is a standard problem of multi-agent game system like robot soccer and it can be realized by many techniques. In this thesis, game flow is described dynamically in terms of critical zones which is formed by potential fields based on the field environment as hills and valleys.
16
Lee, Youngbum. "Coupling between flexible ship and liquid sloshing using potential flow analysis." Thesis, University of Southampton, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.523198.
Full text
17
Bauer, Daniel. "The potential of flexible micro pillars to investigate near wall flow." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2016. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-210372.
Full textAbstract:
The potential of flexible micro pillars for measuring near wall flow phenom- ena was theoretically and experimentally investigated. The bending of the micro pillars is a measure for the local wall shear stress (WSS) or a visualisa- tion of near wall flow phenomena. Polydimethylsiloxane (PDMS) was chosen as material for the sensor. Within the thesis the experimental work with the shear stress sensor mainly has the focus on the transition to turbulence. Closely connected are improvements of the measurement techniques. The transition is thereby investigated qualitatively and quantitatively. Another huge part of the thesis was the improvement of the reliability of the manu- facturing process of the micro pillars. For this purpose new manufacturing methods for single pillars and pillar arrays have been tested. Further on, dif- ferent detection methods for capturing the bending of the pillar were tested, too. The measurements of the transitional flow were performed at flat plate boundary layer in an oil channel. Ondina 913 was used as test fluid. The physical properties of the PDMS changed dramatically while longer exposed to Ondina 913. Hence, it was unfeasible to receive reproducible quantita- tive results. Better results were achieved if the pillars are used as flexible micro tufts revealing the flow and WSS topology directly at the wall quali- tatively. With the pillar sensor it was possible to detect turbulent spots in the transitional state of the flat plate boundary layer. Furthermore, coherent structures and their typical sign in the viscous sublayer could be identified and the occurrence of critical points and back flow could be experimentally verified.
18
Chen, Lei. "Two-Dimensional Electroosmotic Flow in Rectangular Nanochannel with Heterogeneous Surface Potential." The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1418836759.
Full text
19
Shrewsbury-Gee, Joanne. "An investigation of compounds of potential value in experimental cerebral ischaemia." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329110.
Full text
20
Nilsson, Anders. "Power Doppler - Principles and Potential Clinical Applications." Doctoral thesis, Uppsala : Institutionen för onkologi, radiologi och klinisk immunologi : Uppsala universitet, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3775.
Full text
21
Said, Robert, and Adela Rivero. "Turkish Trade Flow and the EU : A study of a potential membership." Thesis, Jönköping University, JIBS, Economics, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-1157.
Full textAbstract:
This bachelor thesis examines how the trade flow of Turkey would change if the country becomes a member in the EU. This is done by analysing the Turkish trade flow with the EU and ROW over the period 1995 – 2005. The main question is if trade creation and trade diversion occurs?
The model used in this paper is a gravity model influenced by Soloaga and Winters (2000) gravity model. To be able to answer the purpose of this paper we used a crosssectional regression and base our analysis on our results.
The conclusion of this paper is that Turkey’s trade flow with the EU will increase if full-membership is accomplished. This leads to trade diversion and trade creation towards the other members-states within EU. We see Turkey as the key to the door for Middle Eastern countries and the EU; this implies that if Turkey becomes a member-state in EU, the trade could increase between these two continents.
Denna kandidatuppsats undersöker huruvida Turkiets handelsflöde kan förändras av ett eventuellt Europeiskt medlemskap. Det är gjort genom att analysera Turkiets handelstrend under perioden 1995 – 2005. Huvudfrågan är huruvida handelsfördelning och handelsökning sker?
Modellen som används i uppsatsen är en gravitations modell influerad av Soloaga och Winters (2000) gravitations modell. För att kunna besvara syftet i uppsatsen har vi använt oss av en tvärsnittsregression och baserat analysen på resultaten.
Sammanfattningsvis ser man att Turkiets handelsflöde med EU ökar av ett eventuellt medlemskap i EU. Detta leder till handelsökning samt handelsfördelning gentemot nuvarande medlemmar. Vi anser även att Turkiet är nyckeln Mellanöstern samt EU, vilket innebär att fullt medlemskap ökar handeln mellan dessa två kontinenter.
22
Weddfelt, Erika. "Recyling potential of phosphorus in food : a substance flow analysis of municipalities." Thesis, Linköpings universitet, Biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-78998.
Full textAbstract:
In this study the opportunities to recycle the phosphorus contained in food handling were identified in four municipalities in the county of Östergötland. The aim was to map the flow and find out whether there were differences between municipalities with food processing industries generating large amounts of waste or phosphorus rich wastewater, or if there were differences between municipalities of different size. It was also investigated to what extent the agricultural demand of phosphorus could be covered by recycling of phosphorus from the food handling system. The result showed that between 27% and 73% of the phosphorus was found in the sludge from wastewater treatment, and that between 13% and 49% of the phosphorus was found in the centrally collected organic waste. This corresponded to 11% of the phosphorus demand on arable land in municipalities with food processing industries generating large amounts of waste or phosphorus rich wastewater, and 8% of the phosphorus demand on arable land in municipalities without such industries.
23
Fürth, Mirjam. "Determining the pressure distribution on submerged 2D bodies using dissipative potential flow." Thesis, KTH, Marina system, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-74700.
Full textAbstract:
Globalization is reaching the furthest corners of the world and with globalizations comes a rising demand on transportation. In shipping; a significant cost both to the ship owners and the environment are the fossil fuels used for propulsion, even a small reduction in the wave resistance can bring considerable reductions both in operating costs and emissions for such ships. When designing a ship it is important to be able to make fast and accurate predictions of its resistance so that more efficient hull forms can be selected early in the design process. A panel method based on potential flow is a fast scheme to determine the wave resistance and is therefore suitable to be used early on in the design process. Here it is shown that potential flow can be improved by including Rayleigh damping, added viscous effects that will make the flow dissipative. Dissipative Green functions are employed in the proposed technique with the resulting velocity potential determined from a combination of a source distribution and a modified distribution of vortices on submerged 2D bodies. NACA hydrofoils, Joukowski hydrofoils and cylinders are used to test the model. The pressure distribution is more in line with experimental results than previous numerical methods without added viscosity for the NACA hydrofoils. The surface profile has very good comparison with existing numerical results for a NACA hydrofoil in subcritical speeds. However the results are very poor for the Joukowski hydrofoil. There is therefore reason to develop this method further in both 2D and 3D.
24
Neale, Samuel. "High speed flow through silicon nitride nanopores as a potential dumb hole." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121513.
Full textAbstract:
Nanopores with diameters ranging from 30 nm to 50 nm were drilled in siliconnitride membranes using a transmission electron microscope (TEM) electronbeam. High pressures of cold helium gas were applied to one side of themembranes to achieve flow through the nanopores. Mass flows for pressuregradients up to 1000 psi were measured with the goal of achieving transonicflow. Measured mass flows were compared to theoretical choked flow valuesand the flow speeds were deduced analytically. The ultimate goal of this workwas to determine whether or not TEM drilled nanopores can act as de Lavalnozzles and accelerate fluid to, or close to the speed of sound. While the siliconnitride nanopores do present some technical difficulties, we estimated that inour nanopores, Unruh temperatures on the order of 7 10^-3 K were reached,leading to phonons being emitted at a rate in the range of 10^5 to 10^6 Hz.Des nanopores de diamètres situés entre 30 et 50 nm ont été perçés dans desmembranes de nitrure de silicium (amorphe) à l'aide d'un microscope électroniqueen transmission (MET). De hautes pressions de gaz d'hélium froidont été appliquées d'un côté de la membrane permettant l'écoulement du fluideà travers le nanopore. Le débit de masse a été mesuré pour des differencesde pressions allant jusqu'à 1000 psi, l'objectif étant d'atteindre un écoulementtransonique. Les mesures ont été comparées à un modèle théorique et lesvitesses d'écoulement ont été déduit analytiquement. Le but de ce projet estde déterminer si les nanopores perçés à l'aide du MET peuvent agir commedes tuyères de Laval et accélerer le fluide à des vitesses proches de celle duson. Bien que les nanopores utilisés présentent des difficultés techniques, il aété estimé qu'il permettraient d'observer une température de Unruh de l'ordrede 7 10^-3 K, et les phonons seraient émis à une fréquence de l'ordre de 10^5à 10^6 Hz.
25
Mallinson, Sarah L. "Tailoring electrolytes and ion permeable membranes for potential redox flow battery applications." Thesis, University of Surrey, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616326.
Full textAbstract:
Energy storage is a solution to the problem of renewable energy intermittency. The vanadium redox flow battery (VRFB) is one such energy storage technology, allowing energy to be stored electrochemically in vanadium electrolytes until required. The advantages of VRFBs include independently scalable energy and power characteristics, high reliability and long life time. The broad aim of this work was to investigate the main problems VRFBs currently present: 1. temperature stability of the vanadium electrolyte, and 2. chemical stability and vanadium cation permeability issues of the ion permeable separator membrane. It was determined that the concentrations of vanadium and sulfuric acid in the electrolyte have a greater impact on thermal stability than the presence of additives. Decreasing the sulfuric acid concentration, improves cold temperature stability of the vanadium electrolyte without impeding stability at elevated temperature.
26
Grundell, Vendela. "Flow and Friction : On the Tactical Potential of Interfacing with Glitch Art." Doctoral thesis, Stockholms universitet, Institutionen för kultur och estetik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-129130.
Full textAbstract:
This thesis aims to analyze how interfacing affects viewer experiences and viewer positions, and how glitch art online makes that effect visible. Glitch art is concerned with disruptions in the systems that govern how for instance photography is produced, circulated and displayed in a digital image flow. The system’s usually undisrupted operation emerges through the friction created between the key components of the study: the viewer, the photo-based mediation, and the interface where the two meet. These components are encircled by the relation between individual and system, whose increased integration with one another requires a sharper eye: a tactical spectatorship in response to how the interface of the image flow can turn the individual into a part of the system. The unfolding of such a spectatorship is investigated through three questions: What can a viewer see and do by interfacing with the website, and with what means? How is the photo-based material on the website produced, displayed and conceptualized? How does the website and its photo-based material – glitched and not glitched – position the viewer haptically and epistemologically? With a cross disciplinary approach, three media phenomenological case studies present glitch artworks in an online environment. The case study on Phillip Stearns’s project Year of the Glitch concerns the website’s index and archive pages as well as still images with a focus on camera reconstruction, verbal conceptualization, and image materiality. The case study on Rosa Menkman’s website Sunshine in My Throat includes index and artwork pages, two artworks with still and moving images as well as a thematization of the entire online environment being glitched. The case study on Evan Meaney’s project Ceibas Cycle focuses on the index page and an interface-based artwork, two video works as well as a portfolio of photographs that are not glitched. The timeliness of the case study materials – created between 2004 and 2012 – is anchored in systems aesthetics, in which technical problems are explored as a cultural critique since the 1960s. The qualitative analysis both emphasizes and problematizes experience, as a complement to quantitative studies about images in relation to a digital flow. The study analyzes how glitch art shapes experiences both by following the interface and by disrupting it. The effect of the underlying system thus appears in a material that has not yet been given an in-depth art historical analysis with a particular focus on the individual viewer. With such a focus, glitch is conceptualized as systemic friction in this study, which clarifies how the artworks online produce knowledge about the interface by providing the individual with a possibility of creating tactical breaks into the image flow. The results of the study consist of the ways of seeing that develop such a possibility – and they gain relevance as they make visible how the flow usually operates in invisible ways. These results point out that the experience of the artworks – and by extension, other experiences of images online – can alert viewers to their own activity within the image flow. If the system sets boundaries for experiences of and through the interface, a tactical spectatorship becomes possible when a glitch gives the individual an opportunity to try different positions towards these boundaries.
27
Okada, Yasuhiko. "A STUDY ON THE POTENTIAL FOR RAPID FLOW PHENOMENA IN GRANULAR SOILS." 京都大学 (Kyoto University), 2002. http://hdl.handle.net/2433/149983.
Full text
28
Karban, Ugur. "Three-dimensional Flow Solutions For Non-lifting Flows Using Fast Multipole Boundary Element Method." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615042/index.pdf.
Full textAbstract:
Driving aim of this study was to develop a solver which is accurate enough to be used in analysis and fast enough to be used in optimization purposes. As a first step, a three-dimensional potential flow solver is developed using Fast Multipole Boundary Element (FMBEM) for calculating the pressure distributions in non-lifting flows.
It is a steady state solver which uses planar triangular unstructured mesh. After the geometry is introduced, the program creates a prescribed wake surface attached to the trailing edge(s), obtains a solution using panel elements on which the doublet and source strengths vary linearly. The reason for using FMBEM instead of classical BEM is the availability of solutions of systems having DOFs up to several millions within a few hours using a standard computer which is impossible to accomplish with classical BEM. Solutions obtained for different test cases are compared with the analytical solution (if applicable), the experimental data or the results obtained by JavaFoil.
29
Travis, Brandon. "The effects of bileaflet prosthesis pivot geometry on turbulence and blood damage potential." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/10024.
Full text
30
Bernasconi, Daniel Joseph. "A higher-order potential flow method for thick bodies, thin surfaces and wakes." Thesis, University of Southampton, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.484982.
Full textAbstract:
Ahigher-order method is developed that models continuous source and doublet singularity distributions over three-dimensional curved surfaces. The singular on-surface influence coefficients are treated by a robust desingularisation algorithm, whereas off-surface coefficients are calculated by means of an efficient subdivision and variable cubature scheme. Whilst higher-order methods have previously been developed fo! thick bodies and Dirichlet boundary conditions, this method is also capable of modelling continuous geometry and singularity surfaces over thin bodies and wakes that require Neumann boundary conditions. The Continuous Surface Method (CSM) has a number of advantages over conventional constant panel methods (CPMs). Firstly, as curved geometries are represented exactly, changing the order of the solution does not modify the physical shape of the configuration. Furthermore, as singularity solutions are continuous, the significant grid-dependency of CPMs does not arise. Finally, the continuous singularity distributions allow velocities to be evaluated accurately across the entire surface without interpolation: this enables the calculation of continuous pressure distributions and the construction ofstreamlines and wakes flowing very close to surfaces, without any problems of divergence. Numerical results comparing the CSM to a CPM have shown that for equal run times, the CSM obtains greater accuracy in pressure distributions than a CPM, and produces much smoother velocity fields. However the CSM was not able to improve upon the efficiency ofthe CPM in determining total aerodynamic forces. A wake relaxation scheme in which wakes are modelled as curved B-spline patches is developed, and is convergent for simple geometries. For.a more complex example of wakes shed from two closely overlapping sails, the wake relaxation converges to within around 0.5% of total aerodynamic load, but the low panel resolutions employed in the CSM are insufficient to model the detail of . the wake roll-up effectively. Three alternative schemes to address this problem are evaluated.
31
Sahrapour, Akbar. "Optimal control of time-dependent viscous flow with potential application to artificial hearts." Thesis, University of Ottawa (Canada), 1995. http://hdl.handle.net/10393/9529.
Full textAbstract:
The present research is concerned with the application of optimal control theory to time-dependent viscous flows. Some specific designs of artificial hearts are described briefly, followed by a review on common hemodynamic problems created by artificial hearts and heart valves. Some mathematical models for certain types of artificial hearts are formulated. Optimal control theory has been applied to some of these models to obtain the necessary conditions of optimality. The optimization problem consists of determining the optimal control policy in order to minimize the value of an appropriate cost functional, which accounts for differences from a desired flow rate and the mean squared shear stresses and vorticity. The necessary conditions of optimality include the Navier-Stokes equations, the associated adjoint equations and an inequality. For the purpose of the numerical solution of the governing equations, a numerical code has been developed, which solves the Navier-Stokes and the corresponding adjoint equations by the Finite Element Method with penalty function formulation. The Navier-Stokes and the adjoint equations were solved iteratively. Each system of equations was solved separately but the two systems were iteratively coupled in the control problem context. At the end of each iteration a new control was computed using the inequality, and the process was repeated until convergence was achieved. Numerical solution of the optimization algorithm was achieved for a two-dimensional model with an initial velocity distribution as the control variable, and a two-dimensional model with a time-dependent boundary velocity applied at some part of the boundary as the control. The latter case was further extended to an approximate three-dimensional model of an artificial heart. In all cases, it was observed that, in the absence of shear stress and vorticity in the cost functional, the desired flow rate was almost achieved, while including these parameters resulted in a decreased optimal flow rate but with smoother velocity distributions. In the case of two- and three-dimensional boundary control, it was found that, when the stress and vorticity levels were minimized, the optimization algorithm could successfully rearrange the flow distribution, smoothen the sharp gradients and remove the vortices that would occur otherwise in the velocity field. This study demonstrates that optimal control of flow systems is practical and can be used as a design tool.
32
Shields, Catherine A. Band Lawrence E. "Export flow distribution and restoration potential of streams along an urban-rural gradient." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,1079.
Full textAbstract:
Thesis (M.A.)--University of North Carolina at Chapel Hill, 2007.Title from electronic title page (viewed Mar. 27, 2008). "... in partial fulfillment of the requirements for the degree of Master of Arts in the Department of Geography." Discipline: Geography; Department/School: Geography.
33
Bloss, Elaine. "Diffusion of solid molecular hydrogen and chemical potential changes in submonolayer helium flow." Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324134.
Full text
34
Furth, Mirjam. "The development of a dissipative potential flow model for wave making resistance prediction." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/366579/.
Full textAbstract:
Steady ship motion in calm water is a classical problem in ship hydrodynamics. Potential flow modelling is a common method to predict the wave resistance of ships. In its conventional form the flow is assumed to be free from damping due to the inviscid assumption of potential flow. It has been argued by the founding fathers of ship resistance predictions that damping plays an important role in determining the wave resistance. Despite this viscosity is often omitted from present wave resistance prediction methods. It is known that damping plays an important role in the formation of the wave pattern and it is therefore of interest to determine the effect on the resistance prediction by including a damping factor in a previously undampened model. In this study, the problem is modelled using Kelvin sources with a translating speed. The fluid flow is modelled using a linearised free surface condition but an exact body condition on the hull. Rayleigh damping is introduced in the model to emulate viscous damping. To calculate the source influences, a new dissipative 3D Green function is derived. The image source part of Green function is separated into the near field and far field disturbance to achieve fast convergence of the integrals. The method is evaluated using thin ship theory to determine the wave pattern behind and the wave profile along a Wigley hull. A panel method is used to determine the wave and residual resistance for submerged ellipsoids and spheres. The results are validated and compared to existing numerical and experimental data from other sources. The results show that it may be possible to capture the residual resistance by including damping in a potential flow model but that more evaluations are needed.
35
Tezdogan, Tahsin. "Potential flow and CFD-based hydrodynamic analyses of mono- and multi-hull vessels." Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24892.
Full textAbstract:
The majority of current techniques used for predicting ship motions rely on assumptions from the potential flow theory. However, this approach is not ideal, since potential flow theory ignores important effects such as breaking waves, turbulence and viscosity, which are significant in problems involving high Froude numbers, those involving large amplitude motions, shallow water problems and problems involving multi-hull ships. These effects should therefore be included in seakeeping and resistance calculations. Reynolds-Averaged Navier-Stokes (RANS) approaches are excellent alternatives to potential flow theory, as they can directly account for viscous effects in their calculations. Towing tank tests are used widely around the world, giving very accurate results. However, these may be costly and time-consuming. Towing tank experiments are also hampered by a limited availability of suitable facilities. Computational simulations offer a fast, low cost alternative to towing tank experi ments. Continued technological advances offer ever-increasing computational power, which can be harnessed for viscous flow simulations to solve the Navier-Stokes equations. Computational Fluid Dynamics (CFD) methods are rapidly gaining popularity for naval architecture, ocean and marine engineering applications. The application of CFD techniques to seakeeping problems allow designers to assess the seakeeping performance of a vessel whilst it is still being designed, enabling any necessary corrective action to be taken before the vessel is actually built. This work mainly aims to perform hydrodynamic analyses of mono- and multi-hull ships, and to develop a CFD-based unsteady RANS numerical model to predict the hydrodynamic performance of these ships. This model will cover seakeeping and resistance calculations in both deep and shallow water regions. Firstly, a detailed literature review of the existing numerical methods which have been developed to solve seakeeping problems of ship is performed. This review also looks in detail at the differences between seakeeping analysis techniques; the reasons for these differences are investigated. Following this, unsteady RANS simulations are performed for various seakeeping and resistance applications. In each specific study, the results obtained using a commercial RANS solver are compared to the results obtained using a potential flow theory code and the available towing tank experiments. Finally, the results drawn from each chapter of this thesis are summarised and discussed, and recommendations are made for future research.
36
Field, Parker Lawrence. "Comparison of RANS and Potential Flow Force Computations for the ONR Tumblehome Hullfrom in Vertical Plane Radiation and Diffraction Problems." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23123.
Full textAbstract:
The commercial CFD software STAR-CCM+ is applied as a RANS solver for comparison with potential flow methods in the calculation of vertical plane radiation and diffraction problems. A two-dimensional rectangular cylinder oscillating in an unbounded fluid is first considered, and the added mass result shown to agree well with the analytical potential flow solution. Hydrodynamic coefficients are then determined for the cylinder oscillating in heave and sway about a calm free surface. Predicted values are observed to coincide with available experimental and linear potential flow results for most amplitudes and frequencies of oscillation examined. A three-dimensional radiation problem is then studied in which 1-DoF heave and pitch motions are prescribed to the ONR Tumblehome hullform in calm water at zero forward speed and Fn 0.3. Combinations of amplitude and frequency of oscillation ranging from small to large are considered. Results are compared with several potential flow codes which utilize varying degrees of linearization. Differences in the force and moment results are attributed to particular code characteristics, and overall good agreement is demonstrated between RANS and potential flow codes which employ a nonlinear formulation. The ONR Tumblehome is next held static in incident head waves of small and large steepness and zero forward speed or Fn 0.3. Force and moment time histories of the periodic response are compared with the same set of potential flow codes used in the radiation problem. Agreement between potential flow and RANS is reasonable in the small wave steepness case. For large wave steepness, the nonlinear wave response is seen to be important and the RANS solution does not generally agree well with potential flow results.Master of Science
37
Bae, Myoungjean. "Potential flow and transonic shocks /." 2009. http://www.library.wisc.edu/databases/connect/dissertations.html.
Full text
38
Brun, Sarah K. "A potential flow model for separated flow around airfoils." Thesis, 1993. http://hdl.handle.net/2429/2631.
Full textAbstract:
Continuing the study carried out by Dr. W.W.H. Yeung, a former Ph.D. student in the department of Mechanical Engineering at U.B.C., some new work has been done on the wake source model, a potential flow model for steady separated flow. This work includes some modifications to the model and applications to new geometries. In the wake source model, the body of interest is conformally mapped to a circle. In the transform plane, singularities (most often sources) are used to represent the wake by creating free stream-lines simulating the separating shear layers. The empirical data required by the modelare the positions of separation points and the specification of the pressure coefficient at these points. Applications of this model include the case of flow normal to a flat plate, a separation bubble at the leading edge of a flat plate airfoil, and an airfoil fitted with a Kriiger flap. The case of the normal flat plate was a test case in which the original model was odified in an attempt to specify a constant pressure on the free stream line after separation. This has been achieved to a limited extent by adding sources to the original model. Future work should include the application of the same method to a spoiler and slotted flap air foil configuration. An earlier model using a doublet as singularity was developed by Yeung for the separation bubble case. It showed very good agreement with experiments in terms of the pressure distribution on the wetted surface of the plate but a high suction peak appeared on the bubble boundary, as well as an unsatisfactory bubble shape. In the present study, no improvement has been obtained by using more singularities, unlike the case for thenormal flat plate. For an airfoil with a Kriiger flap, some satisfactory results can be obtained with a model using two doublets, especially at high angles of attack. Results could be improved at moderate incidence with a better estimate of the bubble shape that forms between the flap and the airfoil lower surface. Thus, it is recommended that flow visualization studies be conducted in the future to evaluate this shape. Experiments should also be carefully repeated in order to assess the accuracy of the model.
39
Cline, Shane. "Potential flow modelling for wind turbines." Thesis, 2011. http://hdl.handle.net/1828/3647.
Full textAbstract:
Lagrangian potential flow methods are a promising alternative to mainstream wind
turbine aerodynamics tools such as blade element momentum methods and grid-based
computation fluid dynamics approaches. Potential flow methods are relatively easy to
setup and robust with respect to geometry. With the advent of numerical techniques
such as the fast multipole method, potential flow methods can be made computationally
fast. Viscous core modelling has led to improvements in accuracy and numerical
robustness. A C++ programming library employing Prandtl-Weissinger lifting line
wing models and tailorable potential flow wake models has been developed under the
name LibAero. The library offers steady-state, periodic, and unsteady flow simulators
that can be used interchangeably with wake models. (Periodic and unsteady simulation
are still under development and validation.) Wake models are constructed from
potential flow elements such as vortex particles, laments, and sheets. Fast multipole
method, symmetry modelling, multigrid method, and relaxation iteration are utilized
to accelerate the computation of element-by-element interactions. The computational
performance is assessed and the numerical results are validated against wind tunnel
experimental data from the MEXICO Project and the Tj reborg wind turbine. The
results of steady-state simulations with respect to a variety of numerical options and
rotor blade designs are presented and conclusions are drawn.Graduate
40
Luo, Yuan-Hsun, and 羅元勳. "Potential Assessment Model of Potential Debris Flow Torrents Based on Hillslope Type Debris Flow in the Catchment." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/r7knv8.
Full textAbstract:
碩士國立屏東科技大學
水土保持系所
105
The study area is located in Kao-ping River Basin. Small scale Debris Flow(or Hillslope Type Debris Flow) occurred in many affected places during the Typhoon Morakot in 2009. Because of its small size, this study is generally called Small Scale Debris Flow. Small Scale Debris Flow not only occurs both sides of the slope, but also entrains sand and gravel into drainage line. Thus, it results in the formation of debris flow torrents and may cause huge loss and loss of life. This study discusses the potential analysis method of potential debris flow torrents in Kao-ping River Basin. Using the ArcGIS to create a planning process and draw analysis units for Small Scale Debris Flow, 35 Small Scale Debris Flow, 35 non-debris flow and 40 verifications were selected for a reorganization model. Small Scale Debris Flow model is established by Fisher’s discriminant analysis. Secondly, the study selects from to 32 potential debris flow torrents and 9 verifications. Each stream catchment is divided into dozens of analysis units, and Small Scale Debris Flow analysis units are interpreted one by one. Then the index of debris flow torrents is developed to assess the potential of each stream. The research using the discriminant analysis shows the classification rate of samples and verification reached 84.3% and 87.5% in a potential analysis model, from Ratio of Landslide Susceptibility Area, Form Factor Ratio, Form Factor of Generating, Hillslope Aspect Ratio of Flow, Flow Length and Hillslope Average Slope of Watershed. Each factor is not only independent, but also has a physical meaning, as the factors in Small Scale Debris Flow discriminant analysis, has a good predictive effect. From the study on the potential assessment model of the potential debris flow torrents, it is observed that The Sum of Small Scale Debris Flow Analysis Unit Area and The Sum of Small Scale Debris Flow Generating Analysis Unit Area are related to the debris flow torrents. The potential classification is based on the two index factors which are consistent with the actual situation of the potential debris flow torrent. The Sum of Small Scale Debris Flow Analysis Unit Area is divided into three grades: low potential debris flow torrent is below 30 hectares, high potential debris flow torrent is more than 250 hectares, median potential debris flow falls in between. In The Sum of Small Scale Debris Flow Generating Analysis Unit Area, low potential debris flow torrent is below 20 hectares, high potential debris flow torrent is more than 150 hectares, and median potential debris flow falls in between. In the extraction factor of the study method, the results of the potential grading shows that the assessment model of The Sum of Small Scale Debris Flow Analysis Unit Area and The Sum of Small Scale Debris Flow Generating Analysis Unit Area are representative in prediction.
41
SU, YI-XING, and 蘇益興. "Potential flow analysis of multi-element aerofoils." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/32068099749370917219.
Full text
42
Yi-TsengLin and 林易增. "Quantum Potential Flow and Its Numerical Analysis." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/47478411343929960727.
Full text
43
Lu, Pei-Sheng, and 呂佩勝. "Potential Disaster Planning Land Management Strategies – Investigate the potential debris flow area." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/47717253808860810794.
Full textAbstract:
碩士中華科技大學
土木防災工程研究所在職專班
99
Taiwan topography is steep, the brook source short class is anxious, is the mountainous region hilly ground approximately composes the entire Taiwan land ratio 76%, suits the high strength development area to be narrow and small, in accordance to the social economy launching, the plain and the basin area several has reached the high density development condition, the cause hilly land the development and the use gradually becomes the tendency, however after 1999 921 volumes of big earthquakes, the hillside soil texture shape is softer, the rock layer is staver, adds the typhoon, the torrential rain to corrode again, the national earth flow disaster occurs keeps pouring, and recent years because of global climate warming phenomenon, cause climatic characteristics change. Taiwan rainfall becomes both quickly and concentrates anxiously, often in 1 day, namely lowers this local annual mean rainfall, like in 2009 the Molake typhoon, in 2010 the plum professional female entertainer typhoon, forms the earth flow to submerge the Xiaolin village, creates local floods and so on Bingdong, Taitung, Yilan. Creates the earth flow disaster, besides Taiwan inborn terrain geology not good and global climate vicissitude (Climate Change), another principal factor is earth flow and so on hilly land area, catchment area dives the potential region overdevelopment result. Present government regarding land development use, although formulates has non-metropolis plan land use law limits and so on control rule, water and soil conservation method, but regarding has completed the exploiter, many by legitimate way agreement maintenance always use, when the typhoon attack or has the bold heavy rain, these areas have the possibility are extremely disaster of the next earth flow damage the area. Dives resident of regarding the position earth flow disaster as well as the private property the potential region, the unusual Local authority is willing to levy this region land evacuation resident, practices to the disaster the highest disaster prevention principle, the present stage Government department rests on creates the earth flow quantity main origin “the rainfall”, evaluation earth flow security value, when the accumulation rainfall reaches the security value, before sentences in advance possibly has the disaster, the basis usually establishes it “the earth flow disaster prevention dispersal to seek asylum the plan”, the start evacuation measure, achieves to the disaster goal, although this measure may the part achieve opportunity of effectively the accurate evacuation, but still had its risk. After the statistical survey, recent years Taiwan regional climate exceptionally changed, besides the typhoon, the bold heavy rain had the probability also changes frequent, even on 1st the rainfall amount reached as high as the local average annual rainfall the astonishing rainfall intensity, in had issued that the earth flow dived in the potential area, when some areas the typhoon or had the bold heavy rain, the accumulation rainfall then reached the earth flow security value evacuation standard, might say that the evacuation number of times was frequent, the such local land should carry out the compulsion collection measure, only then could achieve truly is far away from goal of the earth flow disaster, after and might reduce the disaster occurred when the personnel casualty, the rescue, the disaster, social cost disbursements and so on restoration.
44
Nguyen, Bao Quy. "A modified potential method for transonic flow problems." Thesis, 1986. http://spectrum.library.concordia.ca/4578/1/ML30658.pdf.
Full text
45
Liu, Hsuan-Yun, and 劉軒耘. "Study on Potential Analysis of Debris-Flow Occurrence." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/36252903816705500457.
Full textAbstract:
碩士國立成功大學
水利及海洋工程學系
89
The potential analysis of debris-flow occurrence is aimed to evaluate the debris-flow occurrence probability for a hill slope or gully. The potential analysis is very important and helpful in working on debris-flow hazard prevention and mitigation. This paper describes the conditions of debris-flow occurrence and reviews the affecting factors of debris-flow occurrence. Six factors are selected as major factors on debris-flow occurrence in this paper, such as the effective area of basin, the mean slope of gully, the form factor of basin, the vegetation characteristics, the area of landslides, and the rainfall conditions. The rainfall conditions include the peak 24-hour rainfall, the number of annual rainfall days, and the mean annual precipitation. The weighting value for each factors on the potential of debris-flow occurrence are quantified by the logisitc probability distribution. The GIS technology is also used to deal with the databases of hydrogeological parameters. Besides, this paper develops a classification method, named inverse stream level classification method, to analyze the range of the basin. This classification defines that main stream of the basin is the first level stream, the branches of main stream are the second level stream, and the branches of second level stream are the third level stream, and so on. This method has a direct effect on the confirming of the basins which belong to the branches. Finally, the methods proposed in this paper are used to analyze the potential of debris flow in the Jun-Keng Ravine, Nanto County. The results show that several number of streams, including 19 in second level streams, 12 in third level streams and 1 in forth level streams, which potential of debris-flow occurrence is exceed 50 % in Jun-Keng Ravine during typhoon Herb period. The results of analysis are also compared with the records which made by field investigation. The comparison shows that the method proposed in this paper are reasonable.
46
LIN, GI-KUN, and 林琦焜. "Transonic flow and generalized axially symmetric potential Theory." Thesis, 1986. http://ndltd.ncl.edu.tw/handle/81629534794328321661.
Full text
47
Wu, ming-xun, and 吳明勳. "Potential Debris Flow Torrent Designated Benchmark Of Study." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/29348382043964299217.
Full textAbstract:
碩士逢甲大學
水利工程與資源保育研究所
100
In this study, data collection and statistical analysis to explore the potential debris flow streams designated set of problems and included the potential stream of reason, advantage of the new 158 potential debris flow streams data analysis results, puts forward new potential debris flow streams designated standards and processes in order and set out a standard suitable for the current state of the environment, to provide a future debris flow potential of streams to determine the reference. The results show: 1.In this study, the preservation of objects as a basic threshold of potential debris flow streams designated, trenches streams with preservation of the object, designated standard as the main catchment area of streams and stream beds average slope, shape factor of the catchment area as a supplement the standard, the proposed new mudslide potential streams designated processes and standards. Among them, the standard of stream catchment area of more than 3.0 ha, the riverbed is the average slope of the standard for more than 5 °, while the catchment area of the shape factor standards 0.8. 2.Based on previous studies, with data analysis, the re-classify the original Soil and Water Conservation Bureau of the potential debris flow streams type, stream type and slope landslides classification proposed in this study is based on the total riverbed average slope of 15 °criteria, when the slope is greater than or equal to 15 °, defined as the slope landslides; On the contrary, are classified as stream-type landslides.
48
Chen, Chang-chi, and 陳長棋. "The Occurrence Characteristics Of Potential Debris Flow Torrent." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/05445724447424881103.
Full textAbstract:
碩士逢甲大學
水利工程與資源保育學系
101
Typhoon Morakot 1998 invasion of Taiwan, followed by a long delay high intensity rainfall patterns, resulting in central and southern regions mainly TAG record breaking large rainfall, especially in Kaohsiung, Pingtung County mountains cause significant disasters, making the catchment area so heavy rains and landslides occurred, followed by a stream from both sides of the object preservation landslides damaged destruction disaster situation. Therefore, this research through data collection, compiled in 2008 Announcements 1420 Potential mudslide streams of relevant information, select Kaohsiung(67)and Pingtung County(53)of the two regions for the study, statistical analysis and investigate after typhoon Morakot, the occurrence of debris flow impact of potential debris flow torrent streams associated parameter characteristics. In order to determine the future potential debris flow torrent streams will be able to reference when the mudslide occurred. In this study, in the southern region of the debris flow characteristics analysis results can be divided into two categories: one category is physiographic factors section in the catchment area of 50ha≦A<100ha most likely to occur; stream length 2500m≦L<3000m; average slope at 20°≦S<30°; shape factor between F<0.2; geological section to the high incidence of sedimentary rock. Another was hydrological factors, when the effective accumulated rainfall of 200mm≦R<350mm when more prone to landslides; maximum rainfall intensity part, when 5mm/hr≦I<20mm/hr probability of debris flow occurs when the maximum.
49
Chang, Chi-Shin, and 張啟信. "Comparison of the potential flow and viscous flow computations of the propeller cavitations." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/09729535860309594662.
Full text
50
Hsu, Sen-Yen, and 徐森彥. "Analysis Techniques of Sediment Yields of Potential Debris Flow." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/95576603349745319161.
Full textAbstract:
博士國立中興大學
水土保持學系所
101
Taiwan is located at the junction of the Eurasian and Philippine Sea plates. The geologic characteristics of this area are frequent geological activity, young geological age, fragile rocks, and complicated geological structures. Seismic activity and torrential rain may easily trigger landslides, slope failure, debris flow, and large scale sediment-related hazards. Particulary during summer season from July to October, intense typhoon events in Taiwan may increase the occurrence of sediment-related hazards. Consequently, the sediment-related hazards result in the loss of human life, property and inflict damage to the economy. In this study, the estimation methods of sediment yields and simulation techniques of debris flow in debris-flow potential watersheds were developed to investigate the occurrence mechanisms, transportation process, and sediment yields to enhance the preventive capabilities and skills against the sediment-ralated hazard. For debris-flow non-occurrence condition, the WINHSPF and TRIGRS models were used for predicting the sediment yield resulted from soil erosion and shallow landslide in which four processes, namely, rainfall-runoff, sediment yields, sediment transport, and sediment runoff were taken into accouted. In addition, for debris-flow occurrence condition, the FLO-2D model incorporated with empirical equations were adopted for calculating sediment yields due to debris flow. In the present study, an attempt was made to develop an integrated method considering sediment supplies associated with soil erosion, shallow landslide and debris flow to estimate the sediment yields from a debris-flow potential watershed on a storm event basis. The proposed method was implemented to debris-flow potential watersheds located in the Siou-Lin Township of Hualien County in which numerous data encompassed the hourly rainfall, historical streamflow and sediment monitoring and event-based landslide inventory maps were used for a systematic calibration and validation of numerical models. The validity of numerical models in the integrated method was verified by comparing the sediment yield from numerical simulations with those from field observations of several typhoon events. In the model verifications, a 24 hrs design hyetograph of 100 years return period was employed for the numerical simulation of sediment yield within the study area. For debris-flow non-occurrence scenarios, the numerical results show that the sediment yields from soil erosions and landslides were found to be about 1.1 to 13.8 times of those merely from soil erosion and these demonstrate that the significance of shallow landslide as a source of sediment supply in sediment yields estimation. Moreover, a comparison of sediment yields computed from debris-flow occurrence and non-occurrence scenarios illustrates that the sediment yield from debris-flow occurrence condition was found to be about 14.2 times of that from debris-flow non-occurrence condition and this implies that the sediment-related hazard in debris-flow potential watershed induced by debris flow may cause severe consequences and damages. In this study, in addition to the development of numerical analysis techniques above, several practical applications of the analysis techniques in debris flow disaster such as the delineation of hazard zone, damage assessment, effectiveness assessment of engineering remediation, and estimation of sediment yields in debris-flow potential watersheds were also implemented. Conclusively, the proposed analysis techniques can provide the relevant public agencies or private sectors with the necessary information to draft the prevention/secure emergency plans of debris flow and disaster management policies such as the allocation of rescue resource and the evacuation path during debris flows. Finally, a protective network against sediment-related disaster can be erected to secure the safety of community in the future.