Дисертації з теми "Steady and unsteady states"
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Yassin, Menna. "Steady State Hydroplaning Risk Analysis and Evaluation of Unsteady State Effects." Scholar Commons, 2019. https://scholarcommons.usf.edu/etd/7990.
Повний текст джерелаZeiger, Matthew D. "The Dynamic Character of the Flow Over a 3.5 Caliber Tangent-Ogive Cylinder in Steady and Maneuvering States at High Incidence." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/25150.
Повний текст джерелаPh. D.
Grooms, Daniel Douglas. "Optimization of hybrid dynamic/steady-state processes using process integration." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1752.
Повний текст джерелаMishra, Bikash. "Model development of a polymer electrolyte membrane fuel cell to predict steady and unsteady behavior." Diss., Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-08132008-103611.
Повний текст джерелаHutton, Bridget Margaret. "Evaluation of a vibrating plate extraction column by application of steady state and unsteady state backflow models." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52262.
Повний текст джерелаENGLISH ABSTRACT: Liquid-liquid extraction is a branch of solvent extraction that employs addition of an immiscible solvent, as a separating agent, to a liquid feed. Various types of equipment can be used, however if the process requires more than three stages, typically an extraction column, operated in a countercurrent manner would be employed. In order to scale-up and design a commercial extraction column, it is necessary to quantify the extraction system hydrodynamics and mass transfer characteristics. The principal objectives of countercurrently operated extraction columns concern the mass transfer rate and permissible throughput. The performance of a countercurrent extraction column can be adversely affected by axial mixing, which disturbs countercurrent plug flow. Various methods have been devised whereby it is possible to evaluate the performance of a column extraction and scale it up to ensure that the commercial operation achieves the same separation achieved on a pilot scale. Classical axial dispersion models allow quantification of axial mixing and mass transfer rates. Two Backflow models were derived to describe the performance of a Vibrating Plate Extraction (VPE) Column, one for steady state and one for unsteady state operation. The steady state model consisted of a series of simultaneous equations, which were solved using the Excel solver function. The unsteady state model consisted of 54 ordinary differential equations, which were solved stagewise using a fourth order Runge Kutta procedure. The steady state model was based on a dissociation extraction process, whereby meta-cresol (mcresol) was separated from para-hydroxy-benzaldehyde (PHB). The process used the differing de-protonation constants of the two components and the fact that the solubility of the ionic species of each was low in the organic solvent. The extraction system was quantified using a combination of acid-base and extraction theory. Experimentally determined concentration profiles, measured along the length of the column, were force fitted to the model, thereby allowing determination of the model parameters. The mass transfer coefficients ranged between 0.0098 and 0.189 Imin, and it was found that backmixing of the dispersed phase was negligible, while that of the continuous phase was low (varying between 0 and 0.3). The unsteady state model, used to describe the dynamic response of a VPE, was based on a system whereby tert-butyl hydroquinone (TBHQ) was recovered from a purge stream. Conductivity measurements of the raffinate were used to determine the residence time distribution in the column, and hence allowed determination of the extent of axial mixing. It was preferable that the column be operated with minimum settler volumes, otherwise buffering in the settlers occurred, thereby masking axial mixing effects. This method did not facilitate accurate determination of backmixing, at least two other conductivity measurements in the column needed to be measured.
AFRIKAANSE OPSOMMING: Vloeistof-vloeistofekstraksie is 'n vertakking van oplosmiddelekstraksie wat gebruik maak van die toevoeging van 'n onmengbare oplosmiddel as 'n skeidingagent tot die vloeistofvoer. Verskeie tipes apparaat kan gebruik word, maar as die proses meer as drie stadia vereis, sal 'n ekstraksiekolom, in teenstroom bedryf, tipies gebruik word. Om dit moontlik te maak om 'n kommersiele ekstraksiekolom te skalleer en te bedryf, moet die ekstraksiesisteem se hidrodinamika en massa-oordragkarakteristieke gekwantifiseer word. Die hoof doelwitte van ekstraksiekolomme wat teenstroom bedryf word, gaan om die massa-oordrag en toelaatbare deurset. Die skeidingsdoeltreffendheid van 'n teenstroom ekstraksiekolom kan nadelig beinvloed word deur aksiale vermenging, wat teenstroom propvloei versteur. Verskeie metodes is voorgestel wat dit moontlik maak om die doeltreffendheid van 'n ekstraksiekolom te evalueer en te verseker dat dieselfde skeiding verkry word vir 'n kornmersiele aanleg as vir 'n loodsaanleg. Klassieke aksiale dispersiemodelle laat kwantitatiewe berekening van aksiale vermenging en massa-oordragtempos toe. Twee terugvloeimodelle is afgelei om die werksverrigting van 'n Vibrerende Plaat Ekstraksiekolom (VPE) te beskryf. Die gestadidge toestand model bestaan uit 'n stelsel gelyktydige vergelykings wat opgelos is d.m.v. Excel. Die ongestadige toestand model bestaan uit 54 gewone differensiaalvergelykings, wat stapsgewys opgelos is d.m.v. die vierde orde Runge-Kutta metode. Die gestadigde teostand model is gebaseer op 'n dissosiasie ekstraksieproses, waardeur m-kresol geskei is van p-hidroksiebensaldehied (PHB). Die proses maak gebruik van die verskillende protoneringskonstantes van die twee verbindings en die feit dat die oplosbaarheid van beide die ioniese spesies laag is in die organiese oplosmiddel. Die ekstraksiestelsel is gekwantifiseer deur gebruik te maak van 'n kombinasie van suur-basis- en ekstraksieteorie. Die model is gepas op eksperimenteel bepaalde konsentrasieprofiele, gemeet langs die lengte van die kolom. Die massa-oordragkoeffisiente het waardes aangeneem tussen 0.0098 en 0.189 Imin en daar is gevind dat die terugvermenging van die verspreide fase weglaatbaar was, terwyl die van die kontinue fase laag was (tussen 0 en 0.3). Die ongestadige toestand model wat gebruik is om die dinamiese respons van die VPE te beskryf, is gebaseer op 'n stelsel waar tert-butielhidrokinoon (TBHQ) herwin is vanuit 'n bloeistroom. Geleidingsmetings van die raffinaat is gebruik om die residensietydverspreiding in die kolom te bepaaI en het derhalwe toegelaat dat die mate van aksiale vermenging bepaaI kon word. Die kolom moet by voorkeur met minimale skeiervolumes bedryf word, anders is daar 'n buffereffek in die skeiers, wat die aksiale vermenging verskuiI. Hierdie metode Iaat nie die akkurate bepaling van terugvermenging toe nie en minstens twee ander geleidingsmetings in die kolom was benodig.
McDougall, Steven Robert. "The application of network modelling techniques to steady-and-unsteady-state multiphase flow in porous media." Thesis, Heriot-Watt University, 1994. http://hdl.handle.net/10399/1406.
Повний текст джерелаElsheikh, Mutasim Mohamed. "A Numerical and Experimental Investigation of Flow Induced Noise In Hydraulic Counterbalance Valves." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5683.
Повний текст джерелаGreen, Henry Gregory. "Characteristics of steady and unsteady jets." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/38338.
Повний текст джерелаAbu-Khiran, E. "Steady and unsteady flow losses in automotive exhaust." Thesis, Queen's University Belfast, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268980.
Повний текст джерелаKhezzar, Lyes. "Experiments with steady and unsteady confined turbulent flows." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/46926.
Повний текст джерелаHart, James R. "Longitudinal dispersion in steady and unsteady pipe flow." Thesis, University of Warwick, 2013. http://wrap.warwick.ac.uk/57725/.
Повний текст джерелаWintenberger, Eric Hornung H. G. "Application of steady and unsteady detonation waves to propulsion /." Diss., Pasadena, Calif. : California Institute of Technology, 2004. http://resolver.caltech.edu/CaltechETD:etd-04222004-121013.
Повний текст джерелаHajilouy-Benisi, A. "Radial inflow turbine : performance characteristics under steady and unsteady flow." Thesis, Imperial College London, 1993. http://hdl.handle.net/10044/1/7426.
Повний текст джерелаTewnion, Angus Jamieson. "Steady and unsteady flow simulations in a circular closed conduit." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq20810.pdf.
Повний текст джерелаChen, Hua. "Steady and unsteady performance of vaneless casing radial-inflow turbines." Thesis, University of Manchester, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291004.
Повний текст джерелаCabrita, Pedro Miguel. "Steady and unsteady features of twin-jet STOVL ground effects." Thesis, Cranfield University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426157.
Повний текст джерелаGranlund, Kenneth Ove. "Steady and Unsteady Maneuvering Forces and Moments on Slender Bodies." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/26912.
Повний текст джерелаLateral and transversal forces as well as all three moments have been measured at static angles of attack and sideslip and unsteady pitch ramp maneuvers at a fixed point of rotation at the quarter length of the body. The two bodies are the DARPA Suboff generic submarine shape and a non-Body-of-Revolution scalene ellipsoid with a constant cross-section midbody. An analytical two-mode equation has been shown to accurately describe the normal force and pitch moment as well as side force and yaw moment for the ellipsoid body. It is based on the observation that the center of pressure for the cross-flow contribution is at a fixed location. For the Suboff body, this assumption is invalid. Unsteady forces and moments can be measured to a very small magnitude of uncertainty and were found to differ from steady forces and moments at the time-instantaneous flow angle during the motion.
Ph. D.
Bekiaris, Nikolaos Morari Manfred Morari Manfred. "Multiple steady states in distillation /." Diss., Pasadena, Calif. : California Institute of Technology, 1995. http://resolver.caltech.edu/CaltechETD:etd-09122007-075846.
Повний текст джерелаHakeem, Imtiaz. "Steady and unsteady performance of mixed-flow turbines for automotive turbochargers." Thesis, Imperial College London, 1995. http://hdl.handle.net/10044/1/7402.
Повний текст джерелаGrigore, Daniel. "Analysis of steady and unsteady flows past fixed or oscillating wings." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0024/MQ50613.pdf.
Повний текст джерелаAbdo, Mohammed. "Analysis of steady and unsteady flows past fixed and oscillating airfoils." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0032/MQ64209.pdf.
Повний текст джерелаAbdo, Mohammed. "Theoretical and computational analysis of airfoils in steady and unsteady flows." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84871.
Повний текст джерелаThe first part presents simple and efficient analytical solutions in closed form for the velocity and pressure distributions on airfoils of arbitrary shapes in steady flows, which are obtained using special singularities in the expression of the fluid velocity. A second-order accurate method is first developed for airfoils in inviscid incompressible flows to simultaneously solve the symmetric and anti-symmetric flow components defined by coupled boundary conditions. Then, the method is extended to take into account the viscous and compressibility effects on the pressure distribution. The resulting solutions were found to be in very good agreement with the available exact solutions (for specific airfoils), and with numerical and experimental results at various Mach and Reynolds numbers and moderate angles of attack.
The second part presents a new method of solution for the analysis of unsteady incompressible flows past oscillating rigid and flexible airfoils. The method has been successfully validated by comparison with the results obtained by Theodorsen and by Postel and Leppert for rigid airfoil and aileron oscillations in translation and rotation. The aerodynamic stiffness, damping and virtual mass contributions are specifically determined, as required in the aeroelastic studies. In all cases studied, this method led to very efficient and simple analytical solutions in closed form.
The third part presents an efficient numerical method for the incompressible flows past airfoils at low Reynolds numbers, which are of interest for micro-aircraft applications. The present analysis is based on a pseudo-time integration method using artificial compressibility to accurately solve the Navier-Stokes equations. Solutions are obtained with this method for airfoils at various incidences and very low Reynolds numbers between 400 and 6000. A detailed analysis is presented for the influence of the Reynolds number, incidence and airfoil shape on the pressure distribution, lift and drag coefficients. The flow separation is especially studied; the separation and reattachment positions are compared for various airfoil shapes, incidences and Reynolds numbers.
Grigore, Daniel. "Analysis of steady and unsteady flows past fixed or oscillating wings." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21296.
Повний текст джерелаThis work presents an analytical method for the analysis of steady and unsteady flows past fixed or oscillating wings, which may be efficiently used for complex problems involving the structural dynamics analysis of the wing. The method is first validated for steady flows past fixed wings. Then results are presented for unsteady flows past oscillating wings in comparison with previous results.
Bennetts, Tony Andrew. "Local scour around bridge piers under steady and unsteady flow conditions." Thesis, University of Hertfordshire, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394076.
Повний текст джерелаRedolfi, Marco. "Sediment transport and morphology of braided rivers : steady and unsteady regime." Thesis, Queen Mary, University of London, 2015. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8857.
Повний текст джерелаRice, James Quackenbush. "Investigation of a two-dimensional hydrofoil in steady and unsteady flows." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/27996.
Повний текст джерелаWang, Le. "Bedload sediment transport and bed evolution in steady and unsteady flows." Thesis, Heriot-Watt University, 2016. http://hdl.handle.net/10399/3099.
Повний текст джерелаWhitfield, Cindy Carol. "Steady and Unsteady Force and Moment Data on a DARPA2 Submarine." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/34333.
Повний текст джерелаThe DARPA2 model was tested with different body configurations in two different test sections. The body configurations for both the steady and unsteady experiments were the bare body hull, body with sail, body with stern appendages, and body with sail and stern appendages. Tests were done using trips on the bow and sail and with no trips. The bare hull configuration with no trips was the only body configuration tested in the six-foot-square test section with solid walls. All body configurations were tested in the six-foot-square test section with slotted walls that were used to reduce the blockage effects produced by the DyPPiR and model.
The steady experiments were performed over a range of angles of attack and roll positions. Data were acquired through the series of angles the body encountered during the unsteady testing (-26° < ± <+26° ). The data for the tripped bare hull gave symmetric results while the data acquired for the bare hull with no trips did not. In the unsteady experiments the model was pitched in ramp maneuvers about the 1/4 chord location of the sail from 0° to -25° and from +25° to 0° in 0.3 seconds. Sine wave maneuvers at 3 Hz were also performed, plunging the model up and down with an amplitude of ±0.375 inches. The steady data agreed within uncertainties with previous data that were limited to the David Taylor Research Center (DTRC). There was a higher level of confidence in the steady data taken with trips due to the symmetry of the data. Effects of the sail and/or stern appendages were studied using the steady and unsteady data, but no quantitative value could be calculated due to the uncertainties. The unsteady data
were modeled with a quasi-steady time-lag model, and all the unsteady data were found to lead the quasi-steady data. The unsteady data did have oscillations, but the overall aerodynamic trend was still present. The uncertainties were too large to discuss effects of any appendages, however.
Master of Science
Redolfi, Marco. "Sediment transport and morphology of braided rivers: steady and unsteady regime." Doctoral thesis, Università degli studi di Trento, 2014. http://hdl.handle.net/11572/314279.
Повний текст джерелаMcLain, Brian K. "Steady and unsteady aerodynamic flow studies over a 1303 UCAV configuration." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Sep/09Sep%5FMcLain.pdf.
Повний текст джерелаThesis Advisor(s): Chandrasekhara, M. S. "September 2009." Description based on title screen as viewed on November 5, 2009. Author(s) subject terms: Unmanned Combat Air Vehicle, UCAV, UCAV 1303 Includes bibliographical references (p. 57-58). Also available in print.
Melissa, Matthew (Matthew J. ). "Steady states in rapidly evolving populations." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/115020.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 63-68).
Populations are subject to mutations conferring beneficial effects, as well as mutations conferring deleterious effects. Even if deleterious mutations occur much more frequently than beneficial mutations, the contribution of deleterious mutations to the overall rate of change of the population-wide mean fitness may be limited, due to the efficient action of selection. However, in particularly rapidly evolving populations, the stochastic accumulation of deleterious mutations may negate a significant fraction of the fitness increments provided by beneficial mutations, or even result in an overall decrease in fitness over time. Here we obtain a constraint on beneficial and deleterious mutation rates and selection pressures in order for positive adaptation to counterbalance fitness decline via Muller's ratchet. The steady state that separates parameter regimes of positive adaptation and negative adaptation is characterized by appealing to the exponential dependence of fixation probabilities on fitness effect sizes. We consider a range of fitness-mediated epistatic interactions and the corresponding implications regarding the existence, location and stability of long-term evolutionary fixed points.
by Matthew Melissa.
S.M.
Miermont, Frédéric. "Influence des compensations série des lignes et des compensateurs statiques de puissance sur les réseaux de l'avenir." Grenoble INPG, 1989. http://www.theses.fr/1989INPG0118.
Повний текст джерелаPaniagua, Guillermo. "Investigation of the steady and unsteady performance of a transonic HP turbine." Doctoral thesis, Universite Libre de Bruxelles, 2002. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211407.
Повний текст джерелаStarr, Maxwell. "High-order methods for steady, unsteady and transitional flow over a cylinder." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7859.
Повний текст джерелаPopp, Oliver. "Steady and Unsteady Heat Transfer in a Film Cooled Transonic Turbine Cascade." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/28513.
Повний текст джерелаPh. D.
Santuz, Alessandro. "Extracting muscle synergies from human steady and unsteady locomotion: methods and experiments." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19351.
Повний текст джерелаThe need to move over uneven, continuously changing terrains is part of our daily life. Thus, the central nervous system must integrate an augmented amount of information in order to be able to cope with the unpredictability of external disturbances. A consequence of this increased demand might be a flexible recombination of the modular organisation of movement creation and control. At the expense of motion’s accuracy, it is possible that the system responds by increasing its control’s robustness (i.e. ability to cope with errors). However, the strategies employed by the central nervous system to organise movement are still poorly understood. One possibility is that movements are constructed through a small amount of linearly combined patterns of activations, called muscle synergies. Amongst the several possibilities of perturbing locomotion, the removal of footwear and the use of uneven surfaces are two valid options. In a first step, I conducted a thorough analysis of the methodologies useful for a) the evaluation of spatiotemporal gait parameters using plantar pressure distribution data and b) the extraction of muscle synergies using non-negative matrix factorisation. Afterwards, I analysed the modular organisation of c) shod and barefoot running and d) walking and running over an even- and an uneven-surface treadmill. The modular organisation of locomotion, assessed through the extraction of muscle synergies, changed when perturbations were introduced. Compared to the shod condition, barefoot running underwent, mostly due to the different foot strike pattern, a reorganisation of the time-independent coefficients (motor modules) and a time-shift of the time-dependent muscle activation patterns (motor primitives). Uneven-surface locomotion, compared to even-surface, conserved motor modules, while motor primitives were generally wider, confirming the idea of an increased robustness in motor control during unsteady locomotion.
Hytopoulos, Evangelos. "Laminar, steady and unsteady flow over inclined plates in two and three dimensions." Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-06082009-170928/.
Повний текст джерелаShe, Kaiming. "Numerical studies of vortex shedding from bluff cylinders in steady and unsteady flows." Thesis, Heriot-Watt University, 1987. http://hdl.handle.net/10399/992.
Повний текст джерелаShapiro, Andrew P. "Steady and unsteady heat and mass transfer through porous media with phase change." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/31004.
Повний текст джерелаMICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: leaves 138-139.
by Andrew P. Shapiro.
M.S.
Stettler, Jeffrey W. (Jeffrey Wayne). "Steady and unsteady dynamics of an azimuthing podded propulsor related to vehicle maneuvering." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/33164.
Повний текст джерелаThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 173-177).
While the implementation of azimuthing propulsors powered by internal electric motors (often called "podded propulsors") into the commercial ship market has been swift, the understanding of their hydrodynamics through research, particularly in the area of maneuvering performance, has been very limited. This thesis research investigates the steady and unsteady dynamic maneuvering forces associated with an azimuthing podded propulsor, and provides supporting theoretical insight toward understanding their mechanisms and prediction. Because of the wide range of potential applications of azimuthing podded propulsion in the marine field, dynamic force phenomena applicable to maneuverability of both large and small scale vehicles are investigated. These include quasi-steady vectored maneuvering forces, of importance to all maneuvering vehicles or ships, as well as unsteady or transient maneuvering forces, which have more significance to the maneuverability of smaller vehicles, particularly for precision control applications. The ultimate goal of the research is to provide a comprehensive understanding of the maneuvering forces associated with an azimuthing podded propulsor, such that future maneuvering and control applications, and computational fluid dynamics studies in the field, can be appropriately focused. The research efforts are focused in four main areas. First, a number of relevant dynamic models for the maneuvering of a surface vehicle with an azimuthing propulsor are developed. Second, an extensive test program measures and characterizes the nature of quasi-steady vectored maneuvering forces associated with a podded propulsor in azimuth to ±180⁰ for the entire range of forward propeller speeds, as well as unsteady or transient maneuvering forces due to rapid changes in azimuth angle or propeller rate.
(cont.) This test program is aimed at quantifying the steady and unsteady parameters associated with the developed dynamic models. Third, two flow visualization techniques are utilized to visualize, document, and correlate the helical wake characteristics, velocities and forces for both quasi-steady and unsteady propulsor states. A new fluorescent paint flow visualization technique is developed and applied for small, moderate and4 large propulsor azimuth angles, and a laser particle image velocimetry (PIV) technique is adapted for small and moderate propulsor azimuth angles. Finally, a set of comprehensive physics-based models are developed to foster the understanding of the mechanisms associated with the steady and unsteady force dynamics. The quasi-steady models are based upon a combination of momentum-based, blade-element, and vortex wake propeller theories, as applied to an azimuthing podded propulsor. The unsteady force models are based upon unsteady wake or "dynamic inflow" methods. Additionally, an interesting phenomenon associated with the formation of a vortex ring during rapid propeller rate increase is presented and discussed. The steady and unsteady test results, flow visualizations, and theoretical models, are shown to be consistent in terms of the magnitudes and character of the azimuthing maneuvering forces. Limited comparisons of quasi-steady propulsor forces at small, moderate and large azimuth angles are also made with forces predicted by a modified combined blade-element-momentum (BEM) method, as well as the unsteady vortex-lattice propeller code MPUF-3A, with and without modified inflows to account for propulsor pod wake. The results illustrate inherent complexities related to use of existing computational fluid dynamics tools with azimuthing podded propulsors.
by Jeffrey W. Stettler.
Ph.D.
Hytopoulos, Evangelos. "A turbulence model for steady and unsteady boundary layers in strong pressure gradients." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/40119.
Повний текст джерелаPh. D.
Taroyan, Yeghiazar. "MHD waves and resonant interactions in steady states." Thesis, University of Sheffield, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397503.
Повний текст джерелаMeile, Tobias. "Influence of macro-roughness of walls on steady and unsteady flow in a channel /." Lausanne : EPFL, 2007. http://library.epfl.ch/theses/?nr=3952.
Повний текст джерелаNuhalt, Abdullah O. "Numerical simulation of feedback control of aerodynamic configurations in steady and unsteady ground effects." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/82627.
Повний текст джерелаPh. D.
Rateitschak, Katia. "Construction of nonequilibrium steady states: Thermostating by determministic scattering." Doctoral thesis, Universite Libre de Bruxelles, 2001. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211654.
Повний текст джерелаBuckley, Matthew. "Magnetoconvection in sunspot umbrae : steady and oscillatory localised states." Thesis, University of Newcastle upon Tyne, 2013. http://hdl.handle.net/10443/2130.
Повний текст джерелаJia, Yabo. "Numerical simulation of steady states associated with thermomechanical processes." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEE007.
Повний текст джерелаIn the numerous thermomechanical manufacturing processes such as rolling, welding, or even machining involve either moving loads with respect to the fixed material or moving material with respect to fixed loads. In all cases, after a transient regime which is generally quite short, the thermal, metallurgical, and mechanical fields associated with these processes reach a steady state. The search for these stationary states using the classical finite element method requires the implementation of complex and expensive models where the loads move with respect to the material (or vice versa). The steady-state simulation in one increment has been the subject of much researches over the past thirty years. Methods are now available and some are integrated into calculation codes commercial. Thus, a so-called Moving Reference Frame method proposed by various authors is available in the SYSWELD software. This method makes it possible to calculate the steady-state of thermal, metallurgical, and mechanical states associated with a welding process, by solving a thermal diffusion-convection problem in thermal-metallurgy and by integrating, in mechanics, the constitutive equations of the material along the streamline. Moreover, this method has been used successfully in many applications, it nevertheless has some limitations. Thus the mesh must be structured and the convergence of computations is generally quite slow. In this thesis, we propose to solve the mechanical problem in a frame linked to the solicitations, by relying on a finite element calculation method based on nodal integration and the SCNI (Stabilized Conforming Numerical Integration) technique. This method allows the use of tetrahedron meshes (or 2D triangles) without encountering a locking problem resulting from the plastic incompressibility associated with the von Mises plasticity criterion. Rather than directly calculating the steady-state, the general idea here is to construct the steady-state from a transient analysis by bringing material step by step upstream and by making it exit downstream of a fixed mesh related to the solicitations and of the limited mesh size. The steady-state is therefore only achieved after certain steps of analysis. Apart from a general introduction (Chapter 1) and a state of the art on the existing methods (Chapter 2), we present an approach of simulation of the movement of material within the framework of the classical finite element method on a welding problem (Chapter 3). We also provide relevant thermal boundary conditions for directly calculating the steady-state of temperature distribution. The finite element method based on the nodal integration technique is then described in Chapter 4. The advantages and disadvantages of the method are discussed. The nodal-integration-based finite element is validated by comparing its simulation results with classical finite element methods in large elastoplastic strains, a bending problem, and a thermomechanical simulation of welding. The nodal-integration-based finite element is then developed and applied to simulate material motion (Chapter 5). Three types of movement are considered: translational, circular, and helical. Different methods of field transport are approached and discussed as well as thermomechanical coupling. Perspectives for this work are presented in Chapter 6. The envisaged perspectives aim, on the one hand, to improve the proposed method and on the other hand, to develop the method to simulate other processes. A first application of the material motion method to the simulation of the orthogonal cut is presented there
Zagnoli, Daniel Anthony. "A Numerical Study of Deposition in a Full Turbine Stage Using Steady and Unsteady Methods." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429796426.
Повний текст джерелаAraki, Yoshikazu. "Stability of Steady States and Steady-State Limit of Elastoplastic Trusses under Quasi-Static Cyclic Loading." Kyoto University, 1997. http://hdl.handle.net/2433/77862.
Повний текст джерелаJoussellin, Florence. "Générateur à induction à métal liquide : aspects théoriques et expérimentaux." Grenoble 1, 1986. http://www.theses.fr/1986GRE10124.
Повний текст джерела