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Dissertations / Theses on the topic 'Wall roughness'

Author: Grafiati

Published: 4 June 2021

Last updated: 25 July 2025

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1

Alexander, William Nathan. "Normalization of Roughness Noise on the Near-Field Wall Pressure Spectrum." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/33643.

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Roughness noise can be a significant contributor of sound in low Mach number, high Reynolds number flows. Only a small amount of experimental research has been conducted to analyze roughness noise because of its often low energy levels that are hard to isolate even in a laboratory setting. This study details efforts to scale the roughness noise while independently varying roughness size and edge velocity. Measurements were taken in the Virginia Tech Anechoic Wall Jet Facility for stochastic rough surfaces varying from hydrodynamically smooth to fully rough as well as deterministic rough surfac

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2

Alexander, William Nathan. "Sound from Rough Wall Boundary Layers." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/29246.

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Turbulent flow over a rough surface produces sound that radiates outside the near wall region. This noise source is often at a lower level than the noise created by edges and bluff body flows, but for applications with large surface area to perimeter ratios at low Mach number, this noise source can have considerable levels. In the first part of this dissertation, a detailed study is made of the ability of the Glegg & Devenport (2009) scattering theory to predict roughness noise. To this end, comparisons are made with measurements from cuboidal and hemispherical roughness with roughness Reynold

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3

Placidi, Marco. "An investigation of wall-bounded turbulence over regularly distributed roughness." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/388078/.

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4

Rasnick, Matthew Byron. "The Noise of a Boundary Layer Flowing Over Discrete Roughness Elements." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/33202.

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This study focuses on measuring and normalizing the roughness noise of multiple roughness types across numerous layouts and flow speeds. Using the Virginia Tech Anechoic Wall Jet Facility, far field noise was recording for the flow of a turbulent wall jet boundary layer over cubes, hemispheres, and gravel, with element heights in the range of 14.3 - 55.2% of the boundary layer thickness. The sound radiated from the various layouts showed that the elements acted as independent sources when separated by three element diameters center-to-center or more. When the elements were placed shoulder

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Seddighi-Moormani, Mehdi. "Study of turbulence and wall shear stress in unsteady flow over smooth and rough wall surfaces." Thesis, University of Aberdeen, 2011. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=166096.

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Flows over hydraulically smooth walls are predominant in turbulence studies whereas real surfaces in engineering applications are often rough. This is important because turbulent flows close to the two types of surface can exhibit large differences. Unfortunately, neither experimental studies nor theoretical studies based on conventional computational fluid dynamics (CFD) can give sufficiently accurate, detailed information about unsteady turbulent flow behaviour close to solid surfaces, even for smooth wall cases. In this thesis, therefore, use is made of a state of the art computational meth

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6

Sen, Mehmet Ali. "Proper Orthogonal Decomposition Methodology to Understand Underlying Physics of Rough-Wall Turbulent Boundary Layer." Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/SenMA2007.pdf.

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7

Hersberger, Daniel S. "Wall roughness effects on flow and scouring in curved channels with gravel bed /." Lausanne, 2002. http://library.epfl.ch/theses/?display=detail&nr=2632.

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Thèse sciences techniques, EPF Lausanne, no 2632 (2002), Faculté Environnement naturel, architectural et construit ENAC, Domaine du génie civil. Directeur: A. Schleiss ; rapporteurs: M. Altinakar, G.-R. Bezzola, J. Gessler.

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8

Cabal, Antonio. "Stability of wall-bounded flow modified due to the presence of distributed surface roughness." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0010/NQ40248.pdf.

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9

Westbury, Philippa Sarah. "The effect of Reynolds number and wall roughness on bursts in turbulent boundary layers." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320742.

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10

George, Jacob. "Structure of 2-D and 3-D Turbulent Boundary Layers with Sparsely Distributed Roughness Elements." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/27935.

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The present study deals with the effects of sparsely distributed three-dimensional elements on two-dimensional (2-D) and three-dimensional (3-D) turbulent boundary layers (TBL) such as those that occur on submarines, ship hulls, etc. This study was achieved in three parts: Part 1 dealt with the cylinders when placed individually in the turbulent boundary layers, thereby considering the effect of a single perturbation on the TBL; Part 2 considered the effects when the same individual elements were placed in a sparse and regular distribution, thus studying the response of the flow to a sequence

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11

Carlsson, Per. "Flow Through a Throttle Body : A Comparative Study of Heat Transfer, Wall Surface Roughness and Discharge Coefficient." Thesis, Linköping University, Department of Management and Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8378.

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<p>When designing a new fuel management system for a spark ignition engine the amount of air that is fed to the cylinders is highly important. A tool that is being used to improve the performance and reduce emission levels is engine modeling were a fuel management system can be tested and designed in a computer environment thus saving valuable setup time in an engine test cell. One important part of the modeling is the throttle which regulates the air. The current isentropic model has been investigated in this report. A throttle body and intake manifold has been simulated using Computational F

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12

Waigh, David Ross Carleton University Dissertation Engineering Mechanical and Aerospace. "An Improved correlation for representing surface roughness effects on the law of the wall in fully rough conditions." Ottawa, 1996.

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13

HUNG, SHI-CHANG. "THE UNSTEADY VISCOUS FLOW OVER A GROOVED WALL: A COMPARISON OF TWO NUMERICAL METHODS (BIOT-SAVART, NAVIER-STOKES)." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183957.

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Unsteady two-dimensional laminar flow of an incompressible viscous fluid over a periodically grooved wall is investigated by numerical simulation using two independent finite-difference methods. One is the vorticity-stream function method, and the other involves the vorticity-velocity induction law formulation. The fluid motion is initiated impulsively from rest and is assumed to be spatially periodic in the streamwise direction. The flow field, which includes the time development of the shear layer and the recirculating flow in the zone of separation, is examined in detail during the transien

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14

Apsilidis, Nikolaos. "Experimental Investigation of Turbulent Flows at Smooth and Rough Wall-Cylinder Junctions." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/71713.

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Junction flows originate from the interaction between a fluid moving over a wall with an obstacle mounted on the same surface. Understanding the physics of such flows is of great interest to engineers responsible for the design of systems consisting of wall-body junctions. From aerodynamics to turbomachinery and electronics to bridge hydraulics, a number of phenomena (drag, heat transfer, scouring) are driven by the behavior of the most prominent feature of junction flows: the horseshoe vortex system (HVS). Focusing on turbulent flows, the complex dynamics of the HVS is established through its

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15

Molines, Llodra Jorge. "Wave overtopping and crown wall stability of cube and Cubipod-armored mound breakwaters." Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/62178.

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[EN] The influence of the type of armor on wave overtopping on mound breakwaters is usually represented by the roughness factor. However, different values of roughness factor for the same armor unit are given in the literature. Thus, the roughness factor depends not only on the type of armor, number of layers and permeability but also on the formula and database considered. In the present thesis, a new methodology based on bootstrapping techniques is developed and applied to characterize the roughness factors for different armor units. Differences up to 20% appeared when comparing the optimum

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16

Tian, Zhaofeng, and rmit tian@gmail com. "Numerical Modelling of Turbulent Gas-Particle Flow and Its Applications." RMIT University. Aerospace, Mechanical and Manufacturing Engineering, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080528.150211.

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The aim of this thesis is three-fold: i) to investigate the performance of both the Eulerian-Lagrangian model and the Eulerian-Eulerian model to simulate the turbulent gas-particle flow; ii) to investigate the indoor airflows and contaminant particle flows using the Eulerian-Lagrangian model; iii) to develop and validate particle-wall collision models and a wall roughness model for the Eulerian-Lagrangian model and to utilize these models to investigate the effects of wall roughness on the particle flows. Firstly, the Eulerian-Lagrangian model in the software package FLUENT (FLUENT Inc.)

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17

Stewart, Devin O. "Effects of Spacing and Geometry of Distributed Roughness Elements on a Two-Dimensional Turbulent Boundary Layer." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/35481.

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This thesis is a study of the effects of distributed roughness elements on a two-dimensional turbulent boundary layer. Measurements were taken on a total of ten rough wall configurations: four involving Gaussian spikes, and six with circular cylindrical posts. Rough wall flows are particularly suited to study with Laser Doppler Velocimetry (LDV) due to the fact that measurements are required near a solid surface, as well has in highly turbulent fluid. The LDV system used in this study is a fine resolution (~50 micron), three-component, fiber optic system. All mean velocities, Reynolds stresses

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18

Helvey, Jacob. "Experimental Investigation of Wall Shear Stress Modifications due to Turbulent Flow over an Ablative Thermal Protection System Analog Surface." UKnowledge, 2015. http://uknowledge.uky.edu/me_etds/57.

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Modifications were made to the turbulent channel flow facility to allow for fully developed rough quasi-2D Poiseuille flow with flow injection through one surface and flow suction through the opposing surface. The combination of roughness and flow injection is designed to be analogous to the flow field over a thermal protection system which produces ablative pyrolysis gases during ablation. It was found that the additional momentum through the surface acted to reduce skin friction to a point below smooth-wall behavior. This effect was less significant with increasing Reynolds number. It was al

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BATISTA, Cláudia da Silva. "Estudo teórico e experimental do fluxo de sólidos particulados em silos verticais." Universidade Federal de Campina Grande, 2009. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1815.

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Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-09-26T14:20:44Z No. of bitstreams: 1 CLÁUDIA DA SILVA BATISTA - TESE (PPGEP) 2009.pdf: 3258402 bytes, checksum: 334bd2bbc1cb52f81aa523fd16f4b763 (MD5)<br>Made available in DSpace on 2018-09-26T14:20:44Z (GMT). No. of bitstreams: 1 CLÁUDIA DA SILVA BATISTA - TESE (PPGEP) 2009.pdf: 3258402 bytes, checksum: 334bd2bbc1cb52f81aa523fd16f4b763 (MD5) Previous issue date: 2009-11-06<br>Este trabalho teve por objetivo principal apresentar um estudo teórico e experimental da vazão mássica e do fluxo de produtos granulares para subsidiar o

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Levin, Ori. "Stability analysis and transition prediction of wall-bounded flows." Licentiate thesis, KTH, Mechanics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1663.

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<p>Disturbances introduced in wall-bounded .ows can grow andlead to transition from laminar to turbulent .ow. In order toreduce losses or enhance mixing in energy systems, afundamental understanding of the .ow stability is important. Inlow disturbance environments, the typical path to transition isan exponential growth of modal waves. On the other hand, inlarge disturbance environments, such as in the presence of highlevels of free-stream turbulence or surface roughness,algebraic growth of non-modal streaks can lead to transition.In the present work, the stability of wall-bounded .ows isinvest

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21

Bennington, Jeremy Lawrence. "Effects of Various Shaped Roughness Elements in Two-Dimensional High Reynolds Number Turbulent Boundary Layers." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/34907.

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Modeling the effects of surface roughness is an area of concern in many practical engineering applications. Many current roughness models to this point have involved the use of empirical 'constants' and equivalent sand grain roughness. These underdeveloped concepts have little direct relationship to realistic roughness and cannot predict accurately and consistently the flow characteristics for different roughness shapes. In order to aid in the development of turbulence models, the present research is centered around the experimental investigation of seven various shaped single roughness ele

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22

Hellwig, Maren [Verfasser], Christian [Gutachter] Linsmeier, and Achim von [Gutachter] Keudell. "Influence of 3D geometry and surface roughness on plasma-wall interaction processes on tungsten surfaces / Maren Hellwig. Gutachter: Christian Linsmeier ; Achim von Keudell." Bochum : Ruhr-Universität Bochum, 2016. http://d-nb.info/1105036073/34.

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23

Halama, Lukáš. "Studium chování nenewtonských kapalin ve slit-flow reometru za podmínek nestabilního toku." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-399291.

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The thesis deals with the description of the unstable flow of non-Newtonian fluid in a slit-flow rheometer, which negatively affects its behaviour. The initiators of unstable fluid flow are the roughness of the rheometer slit walls, the slip on the rheometer walls, and the influence of the inlet and outlet region geometry of the rheometer slit. The work contains methodical procedures for mathematical consideration of individual unstable fluid flow initiators and design of change of slit geometry of slit-flow rheometer. Part of the work is also a comparison of the most commonly used rheological

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24

Schuhmacher, Paul. "Rhéologie des écoulements granulaires : variables internes et effets d'échelle." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT300/document.

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Ce mémoire présente des travaux de thèse consacrés à la caractérisation et la modélisation des hétérogénéités spatio-temporelles dans les écoulements granulaires cisaillés entre deux parois rigides. De nombreuses simulations ont permis de révéler le rôle crucial des dimensions de l’écoulement et l’influence des interactions des grains avec les parois (avec leur rugosité) sur le comportement global. Pour des systèmes allant jusqu'à une épaisseur de cent diamètres, des profils de vitesse non homogènes ont été mis en évidence, alors que la contrainte cisaillante est constante dans le volume, mett

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25

Schrader, Lars-Uve. "Receptivity of Boundary-Layer Flows over Flat and Curved Walls." Doctoral thesis, KTH, Stabilitet, Transition, Kontroll, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-25439.

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Direct numerical simulations of the receptivity and instability of boundary layers on flat and curved surfaces are herein reported. Various flow models are considered with the aim to capture aspects of flows over straight and swept wings such as wall curvature, pressure variations, leading-edge effects, streamline curvature and crossflow. The first model problem presented, the flow over a swept flat plate, features a crossflow inside the boundary layer. The layer is unstable to steady and traveling crossflow vortices which are nearly aligned with the free stream. Wall roughness and free-stream

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26

Manu, Dabankah Emmanuel. "Surface Roughness Characterization of hole walls in fibercomposites." Thesis, KTH, Industriell produktion, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-140314.

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In the manufacturing of fibrecomposite structures for the aircraft industry many holes are drilled through the composite for the attachment of the composite to a metal frame. These holes have a Ra specification of the cylindrical walls. The measurement of this roughness is tedious work if made by a stylus profiler. In this thesis, a design concept is created and tested by using OSLO raytracing program. This employed raytracing simulation is used to analyze and study variation of the surface features of the hole and evaluate the corresponding resultant image afterwards using image quality indic

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27

Meile, 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.

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Thèse Ecole polytechnique fédérale de Lausanne EPFL, no 3952 (2007), Faculté de l'environnement naturel, architectural et construit ENAC, Section de génie civil, Institut des infrastructures, des ressources et de l'environnement ICARE (Laboratoire de constructions hydrauliques LCH). Dir.: Anton Schleiss.

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28

Gaied, Lamia. "Influence de la rugosité de surfaces de parois sur les instabilités hydrodynamiques d'un écoulement de Couette-Taylor et de Couette-Taylor-Poiseuille." Thesis, Valenciennes, Université Polytechnique Hauts-de-France, 2020. http://www.theses.fr/2020UPHF0018.

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Ce travail porte sur l’étude numérique et expérimentale d’un écoulement de Couette-Taylor dans une géométrie à surfaces rugueuses, afin de détecter l’effet de la rugosité sur les instabilités hydrodynamiques. Dans un premier temps, nous avons effectué une étude de simulation numérique (CFD) 3D dans le cas d’un écoulement de Couette-Taylor sans débit axial, mais en utilisant plusieurs types de rugosités de surfaces : rugosité isotrope (micro-rugosité), rugosité anisotrope (macro-rugosité), variation de l’amplitude ainsi que le type de la macro-rugosité. Les résultats obtenus montrent bien l’eff

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29

Lecoq, Nicolas. "Etude des interactions hydrodynamiques particule parois par interférometrie laser." Rouen, 1994. http://www.theses.fr/1994ROUES055.

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Le mouvement d'une particule sphérique (de rayon compris entre 1 et 6 mm) dans un fluide visqueux est mesuré par une technique d'interférometrie laser. La sensibilité sur le déplacement relatif de la sphère est de l'ordre de 50 nm. La particule se déplace sur l'axe d'un cylindre fermé. Les interactions hydrodynamiques entre la particule et les parois du cylindre sont étudiées suivant trois approches différentes: la particule se déplace sur l'axe du cylindre. Toutes les parois influencent le mouvement de la sphère. Les résultats sont comparés avec la solution théorique de Sano valable pour une

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30

Mistry, Vinan I. "Simulation and control of stationary crossflow vortices." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/16323.

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Turbulent flow and transition are some of the most important phenomena of fluid mechanics and aerodynamics and represent a challenging engineering problem for aircraft manufacturers looking to improve aerodynamic efficiency. Laminar flow technology has the potential to provide a significant reduction to aircraft drag by manipulating the instabilities within the laminar boundary layer to achieve a delay in transition to turbulence. Currently prediction and simulation of laminar-turbulent transition is con- ducted using either a low-fidelity approach involving the stability equations or via a fu

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31

ZHANG, CHONG-YI, and 張崇義. "Effects of wall roughness and wall movement modes on earth pressure." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/77275227595904785406.

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Wu, Yanhua. "Experimental investigation of highly irregular roughness effects in wall turbulence /." 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3314940.

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Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008.<br>Source: Dissertation Abstracts International, Volume: 69-05, Section: B, page: 3239. Adviser: Kenneth T. Christensen. Includes bibliographical references (leaves 313-321) Available on microfilm from Pro Quest Information and Learning.

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Lee, Ying–Chin, and 李盈欽. "Utilization of Artificial Optical Shadow and Image Processing for Quality Management of Wall Roughness." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/58572071315733766293.

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碩士<br>國立中興大學<br>土木工程學系所<br>104<br>The research is aimed to study the feasibility of integrating artificial optical shadow and image processing to detect the roughness of building interior wall. When the customers purchase the pre-sale and/or secondhand houses, they usually cannot discover uneven interior wall surface until the furniture and lighting have been installed. Poor wall roughness including lousy paint job, uneven wall painting, sagging paint, cracked and convex walls, poor clay priming prior to painting, poor polishing and paste filler application, and uneven polishing of the inside

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Huynh, David Pham. "Spatio-Temporal Response of a Compliant-Wall, Turbulent Boundary Layer System to Dynamic Roughness Forcing." Thesis, 2019. https://thesis.library.caltech.edu/11484/1/DavidHuynh_thesis.pdf.

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<p>This thesis investigates the interaction between an elastic compliant surface and a turbulent boundary layer exposed to dynamic roughness forcing. The goals are to explore a unique perspective of this fluid-structural problem through narrow-band forcing, and to further develop the understanding of dynamic roughness. Water tunnel experiments are designed with flow and surface measurements, both phase-locked to the roughness actuation. This enables a phase-averaged analysis, which leverages the deterministic input to isolate the temporally correlated components of the flow and surface respons

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(11355756), Jonathan J. Gaskins. "The Effect of Near Wall Disturbances on a Compressible Turbulent Boundary Layer." Thesis, 2021.

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This study investigates the effects of near wall disturbances in the form of roughness on a compressible turbulent boundary layer. The studies were carried out using numerical methods which directly solve the Navier-Stokes equations. This provides for unique opportunities to investigate three dimensional structures of the flow as well as avoid the loss of physical fidelity with turbulence modeling. Three cases were ran, a smooth wall case, and two rough wall cases with different heights of the roughness elements between the cases. The results are first visualized with different approaches. The

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Sun, Yi-Shin, and 孫臆勛. "A Study on Stains on External Building Wall Due to Dust and Rainfall─Effects of Surface Roughness and Angle Factors." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/50716473072749017917.

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碩士<br>國立成功大學<br>建築學系碩博士班<br>90<br>The issue of building material’s durability has been taken seriously in recent years. The most noticeable among all kinds of deteriorations is the external building walls being soiled by its surrounding environmental factors, but it is always ignored. However, there is no standard test method available for accessing the dust pollution on external walls in Taiwan. The stain-resistance of wall materials can neither be quantitatively determined nor further analyzed. Thus several Japanese researches and standards were reviewed in this study in order to suggest an

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Essel, Ebenezer Ekow. "Experimental Study of Roughness Effect on Turbulent Shear Flow Downstream of a Backward Facing Step." 2014. http://hdl.handle.net/1993/23265.

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An experimental study was undertaken to investigate the effect of roughness on the characteristics of separated and reattached turbulent shear flow downstream of a backward facing step. Particle image velocimetry technique was used to conducted refined velocity measurements over a reference smooth acrylic wall and rough walls produced from sandpaper 36 and 24 grits positioned downstream of a backward facing step, one after another. Each experiment was conducted at Reynolds number based on the step height and centerline mean velocity of 7050. The results showed that sandpaper 36 and 24 grits in

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Chen, Yi-Hsiang, and 陳益祥. "The Effect of Blade Type and Roughness of Rear Wall on the Performance and the Acoustic Noise of the Cross Flow Fan." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/269nvk.

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碩士<br>國立臺北科技大學<br>冷凍空調工程系所<br>93<br>In order to improve the noise characteristics in the flow field of the cross flow fan (CFF), the present study adopted the CFD software-FLUENT to simulate the internal flow field of CFF and the sound pressure level by changing the blade type and wall roughness. Under the same of the rotational speed, the effects of different blade type and roughness on the fan performance and the characteristics of eccentric vortex were investigated. From the numerical results, it is found that: (1) the blade frequency tone for the fan can be significantly reduced by using t

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"NUMERICAL ANALYSIS OF TURBULENT GAS-SOLID FLOWS IN A VERTICAL PIPE USING THE EULERIAN TWO-FLUID MODEL." Thesis, 2013. http://hdl.handle.net/10388/ETD-2013-01-884.

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Turbulent gas-solid flows are readily encountered in many industrial and environmental processes. The development of a generic modeling technique for gas-solid turbulent flows remains a significant challenge in the field of mechanical engineering. Eulerian models are typically used to model large systems of particles. In this dissertation, a numerical analysis was carried out to assess a current state-of-the-art Eulerian two-fluid model for fully-developed turbulent gas-solid upward flow in a vertical pipe. The two-fluid formulation of Bolio et al. (1995) was adopted for the current study and

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Tsikata, Jonathan Mawuli. "Experimental Study of Turbulent Flow over Inclined Ribs in Adverse Pressure Gradient." 2012. http://hdl.handle.net/1993/14164.

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This thesis is an experimental study of turbulent flows over smooth and rough walls in a channel that consists of an upstream parallel section to produce a fully developed channel flow and a diverging section to produce an adverse pressure gradient (APG) flow. The roughness elements used were two-dimensional square ribs of nominal height k = 3 mm. The ribs were secured to the lower wall of the channel and spaced to produce the following three pitches: 2k, 4k and 8k, corresponding to d-type, intermediate and k-type rough walls, respectively. For each rough wall type, the ribs were inclined at 9

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Andrewartha, JM. "The effect of freshwater biofilms on turbulent boundary layers and the implications for hydropower canals." Thesis, 2010. https://eprints.utas.edu.au/10691/1/01front.pdf.

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The majority of the electricity supplied in Tasmania, Australia, is produced by hydropower. Hydro Tasmania, the power generation utility, operates 29 hydropower stations incorporating 170 km of open channels. These open channels are susceptible to extensive biofilm growth dominated by the freshwater diatoms Gomphonema tarraleahae and Tabellaria flocculosa, which form a gelatinous biofilm several millimetres thick and cause reductions in flow capacity of up to 10%. This thesis presents results of a multidisciplinary study on the effects of freshwater biofilms on hydropower canal capacity

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