Dissertations / Theses on the topic 'Turbulence of the environment'
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Read, Simon. "Transition to turbulence in a turbomachinery environment." Thesis, Cranfield University, 1997. http://dspace.lib.cranfield.ac.uk/handle/1826/10509.
Full textWesterberg, Mats. "Managing in turbulence : an empirical study of small firms operating in a turbulent environment." Doctoral thesis, Luleå tekniska universitet, Innovation och Design, 1998. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18430.
Full textGodkänd; 1998; 20061120 (haneit)
Bosco, Carol. "The Relationship Between Environmental Turbulence, Workforce Agility and Patient Outcomes." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/195013.
Full textWall, Dylan Joseph. "Anisotropic Turbulence Models for Wakes in an Active Ocean Environment." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/104162.
Full textDoctor of Philosophy
A set of advanced turbulence models are implemented and used to study ship wakes in an oceanic environment. The flows in the ocean are subject to a density stratification due to changes in temperature and salinity; the associated effects are included in the turbulence models. The models are validated against laboratory experiments mimicking the stratified ocean environment, and against previous experimental study of wakes subjected to a density stratification. The turbulence models are found to reproduce a number of important behaviors expected under such conditions based on experimental study. Additional modifications are made to the models to include the effect of pre-existing freestream turbulence. Wakes are then simulated under conditions representative of full-scale vehicles operating in an ocean environment. The models are used to make some general predictions concerning late-wake behavior. Specific insights into expected behavior are gained. The wake turbulence is classified using ``fossil turbulence'' and stratification strength criteria from the literature. In keeping with experimentally observed behavior, the stratification is predicted to increase wake persistence. Additional model improvements are proposed based on the predicted late wake behavior.
Choksi, Kashyap Nalin. "A Strategic Approach to Managing Turbulence in the Normative Environment." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/29508.
Full textPh. D.
Genin, Franklin Marie. "Study of compressible turbulent flows in supersonic environment by large-eddy simulation." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28085.
Full textCommittee Chair: Menon, Suresh; Committee Member: Ruffin, Stephen; Committee Member: Sankar, Lakshmi; Committee Member: Seitzman, Jerry; Committee Member: Stoesser, Thorsten
Cerda, Rodrigo Andrés Miranda. "Synchronization in intermittent turbulence and spatiotemporal chaos in the solar-terrestrial environment." Instituto Nacional de Pesquisas Espaciais, 2010. http://urlib.net/sid.inpe.br/mtc-m19@80/2010/04.29.12.38.
Full textIn this work we analyze synchronization due to multiscale interactions in observations of intermittent turbulence and numerical simulations of spatiotemporal intermittency in neutral fluids and space plasmas. This study is carried out in two parts. First, we apply two distinct nonlinear techniques, kurtosis and phase coherence index, to measure the degree of non-Gaussianity and phase synchronization of intermittent magnetic field turbulence observed in the ambient solar wind, in the solar photosphere and in the ground, and intermittent atmospheric turbulence observed in the Amazon rain forest canopy. Next, we analyze a spatially-extended model of nonlinear waves in fluids and plasmas to identify transient coherent structures responsible for the on-off spatiotemporal intermittency observed in the time series of energy. We quantify the degree of amplitude-phase synchronization using the power-phase spectral entropy at the onset of spatiotemporal chaos. The observational and theoretical results indicate that the amplitude-phase Synchronization may be the origin of intermittency in fully-developed turbulence in the solar-terrestrial environment.
Elge, Murat. "Langmuir circulations in a coastal environment during CBLAST." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Sept%5FElge.pdf.
Full textThesis advisor(s): Timothy P. Stanton. Includes bibliographical references (p. 95-99). Also available online.
Hillary, Richard Matthew. "Effects of turbulence and a patchy environment on the dynamics of plankton populations." Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/843526/.
Full textRivas, David Roy. "Theory and simulation of electrostatic wave turbulence in the space shuttle-induced plasma environment." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/49593.
Full textRey, Raposo Ramon. "The interplay between stellar feedback and galactic environment in molecular clouds." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/21022.
Full textMason, Roger Bruce. "An investigation into how marketers cope with an environment of high complexity and turbulence, with special reference to the South African environment." Thesis, Rhodes University, 2004. http://hdl.handle.net/10962/d1003873.
Full textInizan, Maxime. "Turbulence-particle interactions on surfaces." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120445.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 105-110).
The physics of adhesion and detachment of particles in ventilation ducts is important to understand and control contaminant and pathogen dispersal indoors. This thesis presents an experimental characterization of parameters which affect the resuspension of settled micro-particles and spores in a turbulent airflow channel. We examine, quantify, and analyze the role of relative humidity (RH), air temperature, particle size, and surface properties on particle detachment rate and mode. This is done using a combination of high-speed imaging in a turbulent channel where spores and particles are deposited initially followed by image-processing and particle-tracking. First, we show that ambient moisture hinders particle detachment, however, we also find that this is only true for a relative humidity higher than 60% RH. At lower air saturation, we show that, instead, another effect dominates, leading to a different mode of detachment. Instead of individual particle detachment, it is a collision dynamics leading to cluster formation that dominates the pattern of detachment of particles from surfaces. We find that collisions lead to aggregations of particles on the surface in the form of clusters of self-similar sizes. We find that the larger the cluster (above 5 particles) the more anisotropic its shape, similarly to what was observed in prior literature examining clusters of air-suspended particles in channel flows. We examined and quantified the role of initial particle surface concentration, mean air velocity, and particle surface properties on these results. Our study have implications in the control of pathogen and contaminant dispersal in confined geometries, relevant for a wide range of applications.
by Maxime Inizan.
S.M.
Xu, Ying. "Flow/acoustic interactions in porous media under a turbulent wind environment." Diss., Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/3510.
Full textNguyen, Viet. "Simulation of the atmospheric behavior for the environment of a small-scale wind turbine." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/8777.
Full textDepartment of Mechanical and Nuclear Engineering
Zhongquan Zheng
This study investigates a method using computational fluid dynamics (CFD) to model low-elevation atmospheric conditions. There are three goals in this research: to analyze the wind behavior downwind from buildings and trees, to validate the accuracy of the simulations by comparing wind measurements to the simulation for a specific site, and to find a relationship between the wind speed and the power output of a small-scale wind turbine. The first goal is to define a proper CFD model for buildings and trees. The trends in the Strouhal number are found to correlate to changes in building height and the wind resistance of a tree as supported in literature, with minor differences with the addition of a tree. The second goal of this study is to model an actual low-elevation environment to compare the energy output predictions for a small-scale wind turbine versus traditional methods. The simulations are compared to on-site wind measurements at a suburban wind turbine, recorded by the rotor and two anemometers installed on the wind turbine tower. The measurements and simulations presented in this study show an improvement in the accuracy in the estimation of the energy output of a wind turbine versus using traditional methods involving high-elevation wind maps. The third goal is to provide a relationship between the wind speed and the power output of a small-scale wind turbine. To accomplish this task, system identification is implemented. The traditional auto-regressive model with exogenous input variables (ARX), its moving average counterpart (ARMAX), and the output error (OE) model are compared in this study. It is found that the transfer function provided by the ARX model most sufficiently estimates the power output of the studied wind turbine, with power output accuracies of 83%. With all three goals addressed, the feasibility of small-scale wind turbines in different low-elevation environments is assessed. In accomplishing these tasks, the siting of a small-scale wind turbine can be optimized qualitatively and quantitatively.
Eroglu, Ozer. "Analysis of the influence of turbulence and environmental variability on broadband acoustic coherence." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Sep%5FEroglu.pdf.
Full textThesis advisor(s): Kevin B. Smith, Samuel E. Buttrey. Includes bibliographical references (p. 75). Also available online.
Vivoni-Gallart, Enrique Rafael 1975. "Turbulence structure of a model seagrass meadow." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/35483.
Full textIncludes bibliographical references (p. 235-239).
A laboratory study of the hydrodynamics of a seagrass meadow was conducted to investigate the effect of water depth and velocity variations during a tidal cycle on the mean and turbulent velocity fields in and above the vegetation layer. The principal goal was to characterize the turbulence structure of a depth-limited canopy, a gap that presently exists in the knowledge concerning the interaction of a unidirectional flow with an assemblage of plants. The experiments were carried out in an open channel flume with a model seagrass canopy. Proper modeling of the system for both the geometric and dynamic behavior of natural Zostera marina communities allows the results to be extrapolated to the conditions in a coastal, tidal meadow. The results also serve as an important comparative case to the characterization of turbulence within atmospheric plant canopies. The laboratory study included the measurement of the mean and turbulent velocity fields with the use of an acoustic Doppler velocimeter and a laser Doppler velocimeter. Standard turbulence parameters were evaluated including the velocity moments, the turbulence spectra. the turbulent kinetic energy budget and the quadrant distribution of the Reynolds stress. Each of these provided a means of describing the effect of submergence depth and the degree of canopy waving (monami) on the transport of momentum and mass between the canopy and its surrounding fluid environment. In addition. surface slope measurements were made with surface displacement gauges. the plant motion was quantified using video and camera images. and the canopy morphology was recorded from measurements taken from a random sampling of the model plants. The investigation showed a clear link between the shear generated eddies arising at the interface of the canopy and the surface layer and the vertical exchange of momentum. the plant motion characteristics and the turbulence time and length scales. The turbulence field within the seagrass meadow was composed of a shear-generated turbulence zone near the canopy height and a wake-generated zone near the bed In addition. a mean flow due to the pressure gradient from the water surface slope created a region of secondary maxima in the mean velocity profile near the bed. The parameter determining the seagrass turbulence structure was found to be the characteristic depth (H' h). defined such that the effective canopy height. reflects the plant deflection. Across the range of values considered for H/h. the flow characteristics showed a clear transition from a confined to an unbounded canopy flow. This transition was observed in all the principal turbulence parameters. From this analysis. a critical surface layer depth governing the transition between the two extreme canopy flow conditions was identified as half the effective canopy height. H'h = 1.50.
by Ernique Rafael Vivoni Gallart.
S.M.
Heimar, Markus, and Daniel Nilsson. "Survival in Chaos: A Study of Strategy Formation in a Turbulent Business Environment." Thesis, Linköping University, Department of Management and Economics, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1498.
Full textSince the late 1960’s, the hydromechanical term turbulence has been a part of the business administration vocabulary, but until the late 1980’s and early 1990’s, a relatively small amount of research was dedicated to this field. These studies and more contemporary ones conclude that where the business environment is paradoxical and of fast- changing and chaotic nature, successful corporate strategies are shaped by strategic flexibility founded in high innovation rates, networks and alliances, and organisational elasticity and adaptiveness. From this perspective, the purpose of this study was to track and examine the strategy formation processes of a company operating in a turbulent context, and to contribute to an understanding of how these turbulent conditions can be managed. The study was conducted with a hermeneutic, systems- oriented, longitudinal case-study method and with a contextcontent- process perspective in which the process was the key factor. To a large extent, our conclusions coincide with those of other researchers. Forming multidimensional networks and alliances coloured by voluntary initiatives and full attention seem to be an extremely important contribution to survival in turbulent contexts. Nevertheless, it is equally important to break up and build new alliances as the initial objectives of the arrangement have expired or been reached. Furthermore, in contrast to other researchers’ observations, we conclude that high innovation rates do not necessarily lead to a greater potential to be successful in a turbulent context. The issue is instead to present a product offering flexible in itself developed and marketed by a flexible organisation. Innovation rates are decided by self-initiated and unofficial activity on part of the r&d teams and other coworkers, and management’s task is to facilitate for this corporate creativity to develop.
Hübner, Jens. "Buoyant plumes in a turbulent environment." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.603909.
Full textHu, Wilson Kun. "Particle ejection and suspension due to isotropic turbulence." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/12634.
Full textYang, Qingjun (Judy Qingjun). "Impacts of vegetation-generated turbulence on sediment transport." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120638.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 179-188).
Aquatic vegetated habitats, including wetlands and mangroves, are disappearing at an annual rate of 1 to 7%. These ecosystems provide habitats important to fisheries, enhance water quality by filtering nutrients from run-off, and also protect coastal regions from storm surges and waves. To mitigate the loss of these habitats, restoration projects import sediment to eroded areas. The success of the restoration depends on its ability to retain sediment; therefore restoration design requires a good understanding of sediment transport within vegetated landscapes. However, there is currently no quantitative model for sediment transport in vegetated regions, and many restoration projects have failed due to unanticipated erosion from the restored regions. The goal of this thesis is to develop a predictive model for sediment transport in regions with vegetation. First, the affect of vegetation on the critical condition when sediment start to move was explored. To identify the critical condition, an imaging system was designed to track the trajectories of individual moving grain through running water. The critical flow velocity (U[subscript crit]) above which sediment starts to move was identified from the tracked sediment trajectories for both bare (non-vegetated) and vegetated regions. The experimental results showed that for the same type of sediment, U[subscript crit] decreased with increasing vegetation solid volume fraction. This was attributed to the vegetation-generated turbulence, which induced a local, vertical, adverse pressure, or a lift force on the sediment grain, facilitating sediment transport. In contrast, the turbulent kinetic energy (k[subscript t]) was found to be roughly a constant at the critical condition for different vegetation volume fractions, suggesting that k[subscript t] is a more universal metric than T for predicting the critical condition of the sediment transport. A k[subscript t]-based model was developed to predict U[subscript crit] for channels with different vegetation solid volume fractions. The turbulence-based model successfully predicted U[subscript crit] for both bare and vegetated channels, providing a useful tool for ecologists to predict whether a vegetated landscape will erode or not. Second, the impact of vegetation on the bed load transport rate was explored. A system that allows sediment to be bypassed, a cart to distribute sediment, a method that measures the dry weight of wet sand without drying the sediment, a topography system, and an sediment trajectory imaging system were designed. The bed load transport rate (Q[subscript s],) was measured for both bare channels and channels with different vegetation solid volume fractions ([phi]) under different flow rates. At the same [tau], the measured Q[subscript s], increased with increasing [phi], suggesting that vegetation-generated turbulence, which also increased with increasing ]phi], was augmenting the bed load transport. At the same near-bed turbulent kinetic energy, k[subscript t], the Q[subscript s], measured in both bare and vegetated channels agreed within uncertainty, suggesting that k[subscript t] may be a more universal predictor of Q[subscript s] than [tau]. The Einstein-Brown [tau]-based bed load transport model was reinterpreted as a k[subscript t]-based model. The new kt-based model predicted the Q[subscript s] measurements for both bare and vegetated channels. The dependence of Q[subscript s] on k[subscript t] was explained by the statistics of individual grain motion, which showed that Q[subscript s] was predominantly controlled by the number of grains in motion, which correlated with k[subscript t]. The proposed k[subscript t]-based sediment transport model can be used to simulate large-scale landscape evolution and to help ecologists design better coastal restoration strategies. Third, the impacts of vegetation on bed-form characteristics and migration rate were studied. After the measured bed load transport rate converged to an equilibrium value, the bed topography was scanned by a laser topography system. Bed-forms with height less than 2cm were observed and characterized as ripples. For low vegetation solid volume fraction ([phi] by Qingjun Judy Yang.
Ph. D.
Chen, Huijuan. "Experimental and numerical investigations of a ventilation strategy – impinging jet ventilation for an office environment." Doctoral thesis, Linköpings universitet, Energisystem, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-106483.
Full textJabur, Nahida Ali. "Environmental turbulence and innovation durability in selected patient care units." Diss., The University of Arizona, 1999. http://hdl.handle.net/10150/284172.
Full textHedlöf, Carina, and Ulrika Janson. "How to cope with a turbulent environment." Thesis, Linköping University, Department of Management and Economics, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-567.
Full textBackground: Due to constant changes and unpredictability in a turbulent environment, the traditional way of planning does not seem to work anymore. Therefore, new approaches to the external and internal conditions need to develop in order to cope with the environmental turbulence.
Purpose: The purpose of this thesis is to define a turbulent environment and identify how an organisation can cope with this environment. Procedure: We have developed a frame of reference mainly consisting of theories regarding a turbulent environment and change. In addition, we have selected eight guiding factors, which we have used when studying, systemising, and comparing how contemporary literature suggests that an organisation can cope with a turbulent environment.
Results: The conclusions we have come to are that with a definition of the environment as being fast-changing and of chaotic nature, where the changes are continuous, emergent, small, big or somewhere in between, and where paradoxes play an important role, it is necessary to develop an organisational structure, leadership, human resource, and corporate culture, in which the objective always is to create dynamics and to build in an acceptance of change.
Choi, Young-Tae. "Alliance coordination effectiveness and the performance of international strategic alliances: development of the partnership and moderating role of market environment turbulence." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1238.
Full textPianezze, Joris. "Modélisation de la structure verticale de la turbulence optique en milieu naturel." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00830505.
Full textCarpman, Nicole. "Turbulence Intensity in Complex Environments and its Influence on Small Wind Turbines." Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-153215.
Full textMarknaden för vindkraft som en förnyelsebar energikälla växer snabbt, både stor- och småskaligt. Traditionella storskaliga vindkraftverk placeras normalt på homogena platser där vindklimatet och turbulensens karaktär är ganska väl kartlagda och konstruktionsstandarden regleras av standardklasser utifrån olika externa förhållanden. Små vindkraftverk (SWT) å andra sidan placeras ofta i mer komplex eller urban miljö där turbulensen är mer intensiv. En större andel turbulens genererar större utmattningslaster på konstruktionen vilket ökar risken att vindturbinen går sönder. Det är därför av stor vikt att utföra fler mätningar och ytterligare undersöka turbulensen i komplexa miljöer och vilken effekt den kommer ha på de små vindkraftverkens konstruktion. Med anledning av detta så har turbulensdata analyserats från mätningar med sonicanemometrar. Dels på en urban plats, ovanför ett hustak i en medelstor stad (Uppsala, Sverige). Dels vanför en skog i Norunda (utanför Uppsala) på två höjder, nära trädtopparna (33 m) som anses komplex och högre upp (97 m) som anes mer homogen. Resultaten är jämförda med den normala turbulensmodellen (NTM) så som den definieras för standard SWT klasserna av International Electrotechnical Commission i International standard 61400-2: Design requirements for small wind turbines (IEC, 2006). Mätningar av 10 minuters standardavvikelse av den longitudinella vindhastigheten (σu) och turbulensintensiteten (TIu) redovisas, liksom fördelningen av TIu och 10 minuters medelvinden (um) för olika stabilitet för de olika mätplatserna. Resultaten visar att NTM är representativ på 97 m höjd endast för låga vindhastigheter, under 10 m/s, medan modellen underskattar turbulensen för högre vindhastigheter. Det bör också noteras att spridningen är stor i data och att extrema värden av σu och TIu uppmätts vid flertalet tillfällen. För vindhastigheter över 10 m/s så är antalet mätvärden begränsade, men majoriteten av mätvärdena är högre än NTM. På de komplexa mätplatserna (nära trädtopparna och ovan hustaket) så underskattar NTM avsevärt både storleken av σu och dess förändring med ökad vindhastighet på de komplexa platserna (nära trädtopparna och ovan hustaket). Dock är de observerade vindhastigheterna låga såhär nära de skrovliga ytorna så slutsatserna är begränsade. På 97 m höjd är medelvärdet av TIu 19 %, jämfört med 41 % nära trädtopparna och 43 % ovan hustak. De är generellt 10 % lägre under stabila förhållanden (z/L > 0.05) över skog, medan ovan hustak där vindmaterialet är begränsat och 95 % av observationerna var stabilt skiktade så ses inte något stabilitetsberoende. Från dessa resultat kan slutsatserna dras att turbulensens karaktär nära trädtoppar liknar den ovan hustak, men att NTM, så som den definieras för standard SWT klasserna, inte gäller vid dessa komplexa och urbana platser och behöver modifieras för att korrekt uppskatta turbulensintensiteterna och därmed också de laster som påverkar små vindkraftverk placerade på den här typen av platser.
Li, Xiang-Yu. "Numerical approaches to droplet growth in atmospheric turbulence." Licentiate thesis, Stockholms universitet, Meteorologiska institutionen (MISU), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-129868.
Full textPettersson, Kristofer, and Papaioannou Stylianos. "Corporate Social Responsibility of SMEs during Times of Turbulence : - A Case Study of Small and Medium-sized Exporters in a Changing Environment." Thesis, Linnéuniversitetet, Ekonomihögskolan, ELNU, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-20643.
Full textCatalan, Ros Leyre. "Analysis of human exposure at local exhaust ventilation by means of 3D air velocity measurements, tracer gas tests and controlled turbulence environment." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-19713.
Full textRenoud, Robert W. "Boundary layer response to an unsteady turbulent environment." Thesis, Monterey, California. Naval Postgraduate School, 1988. http://hdl.handle.net/10945/22931.
Full textBlackmore, Tom. "Grid generated turbulence and actuator disc representations of tidal turbines." Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/361942/.
Full textGwilliam, David J. "Separating boundary layer response to an unsteady turbulent environment." Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/27259.
Full textVan, Der Mescht Deon. "Mountain wave turbulence in the lee of the Hex River Mountains." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20240.
Full textENGLISH ABSTRACT: Despite recorded mountain wave related aircraft accidents in South Africa, very little literature exists on South African mountain waves. This study discusses the results of a mountain wave study in the Hex River Mountains in the Western Cape province of South Africa. The aim of this study was to measure mountain wave turbulence on the lee side of the mountains by conducting weather balloon soundings on the upwind and lee sides of the mountains. These soundings were performed over four days in the winter and spring, with each field day representing different synoptic scale weather conditions. Lee wave rotors were detected from several of the lee wave soundings. Significant values of horizontal vorticity around a north-south axis (y-component horizontal vorticity) were detected. The instrumentation was highly sensitive and able to measure even weak up and downdraft velocities associated with the rotors. Strong downdrafts were measured some mountain waves, but no strong downdrafts were detected near rotors which occurred below the mountain waves. The two dimensional positions of balloons were only available after a considerable amount of reanalysis. If this data can be made available onsite shortly after soundings, it can be used to decide where to move launch sites to, in order to obtain optimal results.
AFRIKAANSE OPSOMMING: Ten spyte van gedokumenteerde berggolf-verwante vliegongelukke, bestaan baie min literatuur oor Suid Afrikaanse berggolwe. Hierdie tesis bespreek die resultate van ‘n berggolfstudie in die Hexrivier Berge in the Weskaap Provinsie van Suid- Afrika. Die doel van hierdie studie was om die berggolfturbulensie aan die lykant van die berge te meet deur middel van weerballonopstygings aan beide die winden lykante van die berge. Hierdie opstygings is oor ‘n tydperk van vier winter en lente dae uitgevoer, met elkeen van die dae wat verskillende sinoptiese weersomstandighede verteenwoordig het. Rotors is waargeneem in die data van verskeie ballonopstygings wat aan die lykant uitgevoer is. Beduidende waardes van horisontale vortisiteit rondom ‘n noord-suid as (y-komponent horisontale vortisiteit) is gemeet. Die instrumentasie was hoogs sensitief en kon selfs swak op- en afstrominge meet. Sterk afstrominge is waargeneem in berggolwe, maar nie in die omgewing van rotors wat onmder die berggolwe voorgekom het nie. Die twee-dimensionele posisies van ballonne was slegs na aansienlike heranaliese van die data beskikbaar. Indien hierdie data kort na opstygings beskikbaar is tydens veldwerk, kan dit help met besluite oor alternatiewe posisies waarvandaan ballonopstygings gedoen kan word ten einde optimale resultate te bekom.
Stewart, Robert L. III. "DECELERATING OPEN CHANNEL FLOW OVER GRAVEL: TURBULENCE STRUCTURE & SENSOR DEVELOPMENT." UKnowledge, 2014. http://uknowledge.uky.edu/ce_etds/25.
Full textMillard, Deborah J. "An investigation into flow in confined environments using laser doppler anemometry and computational fluid dynamics." Thesis, London South Bank University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245092.
Full textGrose, Mitchell. "Forecasting Atmospheric Turbulence Conditions From Prior Environmental Parameters Using Artificial Neural Networks: An Ensemble Study." University of Dayton / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1619632748733788.
Full textConnell, R. J. "Unstable equilibrium : modelling waves and turbulence in water flow." Diss., Lincoln University, 2008. http://hdl.handle.net/10182/592.
Full textBabajee, Jayson. "Detailed numerical characterization of the separation-induced transition, including bursting, in a low-pressure turbine environment." Phd thesis, Ecole Centrale de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00984351.
Full textSinha, Nityanand. "Towards RANS Parameterization of Vertical Mixing by Langmuir Turbulence in Shallow Coastal Shelves." Thesis, University of South Florida, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3605268.
Full textLangmuir turbulence in the upper ocean is generated by the interaction between the wind-driven shear current and the Stokes drift velocity induced by surface gravity waves. In homogenous (neutrally stratified) shallow water, the largest scales of Langmuir turbulence are characterized by full-depth Langmuir circulation (LC). LC consists of parallel counter-rotating vortices aligned roughly in the direction of the wind. In shallow coastal shelves, LC has been observed engulfing the entire water column, interacting with the boundary layer and serving as an important mechanism for sediment re-suspension. In this research, large-eddy simulations (LES) of Langmuir turbulence with full-depth LC in a wind-driven shear current have revealed deviations from classical log-layer dynamics in the surface and bottom of the water column. For example, mixing due to full-depth LC induces a large wake region eroding the classical bottom (bed) log-law velocity profile. Meanwhile, near the surface, Stokes drift shear serves to intensify small scale eddies leading to enhanced mixing and disruption of the surface velocity log-law. The modified surface and bottom log-layer dynamics induced by Langmuir turbulence and full-depth LC have important implications on Reynolds-averaged Navier-Stokes simulations (RANSS) of the general coastal ocean circulation. Turbulence models in RANSS are typically calibrated under the assumption of log-layer dynamics, which could potentially be invalid during occurrence of Langmuir turbulence and associated full-depth LC. A K-Profile Parameterization (KPP) of the Reynolds shear stress in RANSS is introduced capturing the basic mechanisms by which shallow water Langmuir turbulence and full-depth LC impact the mean flow. Single water column RANS simulations with the new parameterization are presented showing good agreement with LES
Akan, Cigdem. "Surface Mass Transfer in Large Eddy Simulation (LES) of Langmuir Turbulence." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/3944.
Full textGoettel, Michael Thomas. "Analysis of the swimming behavioral response of western blacknose dace in a turbulence modified flow field." Thesis, State University of New York at Buffalo, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1539819.
Full textFish passage success rates through hydraulic infrastructure have been historically low due to flow field conditions that exceed the physical or behavioral capabilities of a given species. Significant efforts to design and modify hydraulic structures for enhanced passage rates have failed to achieve the desired results, with a primary reason being a poor understanding of how fish respond to complex hydraulic conditions. Many contemporary research efforts have targeted the inter-relationship between hydraulics and fish behavior in the laboratory using live fish trials in an attempt to better comprehend these interactions and ultimately provide a basis for the development of biologically-based design criteria. In this study experiments were conducted to assess the behavioral responses along swimming trajectories of western blacknose dace ( Rhinichthys obtusus) in turbulent flow conditions. The objective was to test the hypothesis that the dace would preferentially adjust their swim paths to minimize their exposure to elevated turbulent conditions. Experimental data were collected through digital imaging of dace trajectories for fish that had been released into a shallow flume and allowed to swim through turbulence enhanced flow fields. Additionally, detailed velocity measurements were collected with an acoustic Doppler velocimeter to allow the comparison of dace trajectories to flow field conditions represented by average metrics of turbulent kinetic energy and Reynolds shear stresses. Analysis of the data consisted of the quantification of the proportion of the time that a dace's swim path selected a direction toward a lower magnitude turbulence condition when such an option existed. Fish paths were also graphically compared to turbulence contour plots to qualitatively assess the presence of swim path preferences or patterns. Lastly, video footage of each trial was evaluated to qualitatively assess the presence of novel behaviors that could have implications for the swimming trajectories observed. Results indicate that the dace did not preferentially avoid turbulence at statistically significant levels under the conditions experienced in the flume; however, data do suggest that some behavior relative to turbulence was non-random. Qualitative observations of video footage suggest that non-hydraulic factors, such as the presence of conspecifics and light intensity, also influence the swim path trajectories of the western blacknose dace. Future research will require more targeted turbulent conditions, simultaneous multivariate observations and analyses that factor in non-hydraulically-based behavior and the incorporation of coupled behavioral and hydraulic data at reduced time and length scales for primary variables. It is envisioned that the results of this study can provide guidance for future studies aimed at developing biologically based design criteria for enhanced fish passage at hydraulic infrastructure.
Newman, Paul Lockwood. "Numerical simulation of diffusive shock acceleration in a turbulent astrophysical environment." Thesis, Imperial College London, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307793.
Full textFairbank, Nicola. "Viral infection and predation of phytoplankton residing in a turbulent environment." Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.548765.
Full textMachin, Alison Isabel. "Role identity in a turbulent environment : the case of health visiting." Thesis, University of Newcastle upon Tyne, 2009. http://hdl.handle.net/10443/3972.
Full textSmith, Heather Dianne. "Flow and sediment dynamics around three-dimensional structures in coastal environments." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1196261689.
Full textHuang, Yongxiang. "ARBITRARY ORDER HILBERT SPECTRAL ANALYSIS DEFINITION AND APPLICATION TO FULLY DEVELOPED TURBULENCE AND ENVIRONMENTAL TIME SERIES." Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2009. http://tel.archives-ouvertes.fr/tel-00439605.
Full textWang, Jialin. "Building integrated wind energy." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/building-integrated-wind-energy(81978798-e68a-4189-87b0-4159b280b6e9).html.
Full textCrawford, Thomas Joseph. "An experimental study of the spread of buoyant water into a rotating environment." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/264526.
Full textAugier, Pierre. "Turbulence en milieu stratifié, étude des mécanismes de la cascade." Phd thesis, Ecole Polytechnique X, 2011. http://tel.archives-ouvertes.fr/tel-00697245.
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