Dissertations / Theses on the topic 'PIV'
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Ruy, Danilo Virges [UNESP]. "Estrutura hamiltoniana da hierarquia PIV." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/92036.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Esta dissertação trata da construção de hierarquias compatíveis com a equação PIV a partir dos modelos: AKNS, dois bósons e dois bósons quadráticos. Também são construidos os problema linear de Jimbo-Miwa dos três modelos e discutimos a hamiltoniana correspondente a equação PIV a partir do formalismo lagrangiano
This dissertation contains the construction of compatible hierarchies with the PIV equation from the models: AKNS, two-boson and quadratic two-boson. Also it is build the Jimbo-Miwa linear problem for the three models and we discuss the hamiltonian corresponding to fouth Painlevé equation from the Lagrangian formalism
Ruy, Danilo Virges. "Estrutura hamiltoniana da hierarquia PIV /." São Paulo : [s.n.], 2011. http://hdl.handle.net/11449/92036.
Full textBanca: Iberê Luiz Caldas
Banca: Roberto André Kraenkel
Resumo: Esta dissertação trata da construção de hierarquias compatíveis com a equação PIV a partir dos modelos: AKNS, dois bósons e dois bósons quadráticos. Também são construidos os problema linear de Jimbo-Miwa dos três modelos e discutimos a hamiltoniana correspondente a equação PIV a partir do formalismo lagrangiano
Abstract: This dissertation contains the construction of compatible hierarchies with the PIV equation from the models: AKNS, two-boson and quadratic two-boson. Also it is build the Jimbo-Miwa linear problem for the three models and we discuss the hamiltonian corresponding to fouth Painlevé equation from the Lagrangian formalism
Mestre
ALIOUCHOUCHE, NADIA. "Etude d'ecoulements par methode piv." Paris 11, 1997. http://www.theses.fr/1997PA112142.
Full textPan, Xiao Bo. "Advanced technology applied to PIV measurement." Thesis, Heriot-Watt University, 1996. http://hdl.handle.net/10399/737.
Full textCardesa, Dueñas José Ignacio. "2D PIV study of grid turbulence." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610384.
Full textBalaštík, Milan. "Obliba ovocných piv v České republice." Master's thesis, Česká zemědělská univerzita v Praze, 2017. http://www.nusl.cz/ntk/nusl-262870.
Full textZhang, Jin Bai. "Procédé de traitement anaérobie des boues et de valorisation du biogaz." Thesis, Vandoeuvre-les-Nancy, INPL, 2011. http://www.theses.fr/2011INPL106N/document.
Full textThe present work is focused on developing an original micro to mesoscale approach to investigate various phenomena and then to intensify the performance of a reactor. At mesoscale, the emphasis is given to the interactions between granular sludge particles as well as the biogas production efficiency in a 2D reactor under various hydrodynamic conditions at different concentrations of substrate. Then, within the microdevices, a single sludge particle of various sizes was used under different operating conditions such as superficial liquid velocity and concentration of substrate. The effect of different hydrodynamic conditions and concentration of substrate was studied
Li, H. "CFD and PIV investigations of pipe discontinuities." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.484975.
Full textFetter, Daniel Karl. "PIV measurements within a water analog engine." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0018/MQ54108.pdf.
Full textFranz, R., and U. Hampel. "Strömungsprofilmessungen mittels PIV-Verfahren an einem Stabbündel." Forschungszentrum Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-113907.
Full textPeng, Haiya. "PIV measurements of flow through forming fabrics." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/37737.
Full textDietrich, Nicolas. "Étude locale et expérimentale des Phénomènes interfaciaux." Phd thesis, Institut National Polytechnique de Lorraine - INPL, 2008. http://tel.archives-ouvertes.fr/tel-00357211.
Full textDes bulles et des gouttes ont été étudiées expérimentalement depuis leur formation, en passant par leur déformation jusqu'à leur coalescence. La formation de bulles dans des micro-mélangeurs a été étudiée et caractérisée par l'obtention de champs de vitesses. Différents paramètres, tels que le cisaillement, la géométrie de la zone de formation, les débits ou encore les propriétés physiques ont été testés afin de développer des lois d'échelles.
La traversée d'une interface liquide-liquide par une inclusion a été abordée par des expériences originales, permettant de décrire la dynamique du phénomène, de définir des nombres adimensionnels et de mettre en évidence des instabilités interfaciales. L'effet Weissenberg a également été étudié aux différentes échelles afin de comprendre les phénomènes conduisant à son amplification.
Enfin, en milieu viscoélastique et rhéofluidifiant, nous avons caractérisé l'écoulement autour d'une inclusion isolée solide par l'obtention de champs de vitesses. Ces résultats ont permis de confirmer l'origine viscoélastique du sillage négatif et de prédire ses caractéristiques.
Bossard, Jonathan. "Caractérisation expérimentale du décrochage dynamique dans les hydroliennes à flux transverse par la méthode PIV (Particle Image Velocimetry). Comparaison avec les résultats issus des simulations numériques." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00848242.
Full textDanhone, Ricardo. "Análise de circulação induzida po MHD em fluido condutor através de velocimetria a laser." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-03032017-150558/.
Full textThe aim of this work involves the analysis of fluid flow, using sea water stimulated by localised magnetohydrodynamic induction within an experimental glass sided receptacle. The above mentioned apparatus simulated one segment of a three dimensional apparatus capable of creating a flow pattern very similar to that of a vortex ring. Particle Image Velocimetry techniques using a copper vapour laser with computerised image and data acquisition system were used to analyse the flow in the experimental segment. The final aim of this line of research is to be able to eventually model the shape of bodies in movement within a fluid when combined with the use of a magnetohydrodynamically induced flow field in such a way as to significantly reduce fluid drag forces on the body. Circulatory movement was induced in the fluid within the confines of the experimental tank using a locally applied Lorentz field force between electrodes to accelerate the fluid. Both the electrical and magnetic fields were controlled independently using separate external rectified a.c. circuits. The aim of the fluid movement described above was to induce low static pressure over a specific surface area. The analysis of the fluid movement, including the measurement of velocities in different points of the circuit was attained using specialised optical equipment linked to a computerised data acquisition and analysis system. The results, which included exceptionally low velocity readings, showed thatsuch equipment possesses the potential for developed for the attainment of better results in the future.
Cosadia, Imran. "Variabilité cyclique de l'aérodynamique interne d'un moteur diesel : mise en oeuvre de diagnostics optiques pour l'analyse spatiale et temporelle." Toulouse, INPT, 2006. http://www.theses.fr/2006INPT061H.
Full textUnderstanding in-cyclinder flows is a major goal to reduce pollutant emissions and implies the physical characterization of the cyclic variations associated to the large-scale air motions within engines. This thesis proposes an experimental analysis of the swirling flow in a Diesel transparent engine by laser velocimetry. The stability of the flow is shown to be linked with structure fluctuations, revealed by the computation of circulation statistics, and quantified thanks to proper orthogonal decomposition (POD). Spatial analysis is completed by a temporal resolution of the compressed flow-field. A coupling approach between the temporal velocity fields and a phase-invariant application of the POD is then suggested to solve the large-scale dynamics and to describe the parameters space. Finally, the circulation temporal analysis proves that a significant number of modes is necessary to achieve a reliable representation of the flow variations
Seim, Bjarte Grytli. "Study of Hydrofoil Wakes Using PIV and CFD." Thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9929.
Full textIn this master thesis the wake of a hydrofoil have been investigated using PIV. The main goal of this work have been to investigate how vortex generators can create mixing and smoothing of the velocity deficit in hydrofoil wakes. This study is motivated by the rotor stator interactions in Francis turbines with the idea that smoother wakes from the stator can reduce the forces on the rotor and hence increase the life span of Francis turbines. A literature survey of foil theory and wake flows have been carried out. This survey motivated the use of a normalization of the velocity in the wake. Experimental work was carried out at the water tunnel facility at Saint Anthony Falls Laboratory at the University of Minnesota. Tests were performed on a NACA0015 hydrofoil with four different vortex generator configurations, for a range of different angles of attack and velocities. Lift and drag forces on the hydrofoil was measured using a force balance. Because the drag measurement had poor accuracy, it could not be used to compare the different vortex generator configurations in terms of drag. As a result the drag was investigated using the velocity deficit in the wakes. The quality of this analysis have been discussed with the use of CFD. CFD is also used to gain insight into how pressure and velocity is distributed in the water tunnel. The PIV images from the tests have been processed into vector fields with the commercial PIV software DaVis7. For analyzing the PIV data further, different post-processing schemes in DaVis7 was investigated together with programs developed in Matlab. In order to compare the wakes resulting from the use of different vortex generators with measurable quantities, the use of a standard wake profile has been investigated. The standard wake profile is symmetrical and could hence only describe wake measurements done at an angle of attack close to $0^{circ}$. Furthermore it turned out that most vortex generators resulted in a wake that could not be described with the standard wake profile. The vortex generator configurations that gave the best smoothing of the hydrofoil wake for the investigated operation points turned out to be a $1unit{mm}$ V-shaped vortex generator. This vortex generator also caused less drag than than the other vortex generators tested. However, the use of vortex generators resulted in increased drag compared to the plain hydrofoil for the analyzed operating points. The velocity deficit in the wake is shown to get so well smoothed out for some tested cases that it is considered worth while to continue the investigation on vortex generators capability to increase the lifespan of Francis turbines.
Worth, Nicholas. "Tomographic PIV measurement of coherent dissipation scale structures." Thesis, University of Cambridge, 2010. https://www.repository.cam.ac.uk/handle/1810/237242.
Full textGamboa-Marrufo, Mauricio. "Wind engineering applications of particle image velocimetry (PIV)." Thesis, University of Oxford, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403974.
Full textSingh, Fatehjit. "Micro-PIV measurement of flow through forming fabrics." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45656.
Full textMasullo, Alessandro. "Advanced algorithms for the analysis of PIV images." Thesis, University of Bristol, 2018. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.743057.
Full textWilliams, Braydon J. "Uncertainty of Stereo PIV Calibration and Self-Calibration." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/5263.
Full textHemmer, Cédric. "Contribution à l'étude du couplage thermo-mécanique entre un émetteur de chauffage et son environnement." Thesis, Reims, 2015. http://www.theses.fr/2015REIMS023.
Full textThe electric heating devices, which can seem relatively simple at first sight because composed only by an electric heating resistance in a metallic box, are in reality much more complex heat exchangers. Besides the regulation process part the role of which is to determine at every moment the quantity of energy to bring to the room to supply the desired temperatures of air, the device has to ensure a uniformity of temperatures and velocities of air in agreement with the thermal comfort wished, whatever his way of functioning and the outside thermal conditions. This good distribution of temperatures and velocities of air will give a good thermal comfort level which is the condition of a sober and controlled energy consumption. The objective of this thesis is thus to better understand in a first phase the thermo-aeraulics phenomena acting on the scale of the radiator and in the second phase those acting on the scale of the room. To improve this understanding, a tool of digital simulation which can be used to the conception of radiators by the company CAMPA has been developed
SORBE, JORGE. "An experimental study in the near field of a turbulent round free jet." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-17424.
Full textBourget, Baptiste. "Ondes internes, de l'instabilité au mélange. Approche expérimentale." Thesis, Lyon, École normale supérieure, 2014. http://www.theses.fr/2014ENSL0912/document.
Full textInternal waves are believed to be of primary importance as they affect energy transfer, especially their dissipation mechanism. Therefore it is crucial to identify and measure the different processes evolving a transfer to smaller scales and leading to oceanic mixing. We have chosen to focus on one of these mechanisms: the Parametric Subharmonic Instability (PSI). This instability allows the generation from a primary wave of two secondary internal waves, with different frequencies and waves vectors, by nonlinear resonant interaction. The experimental study of this instability has helped to highlight the importance of some parameters (frequency, amplitude, beam width) for the development and the selection of secondary waves. Thus these parameters affect the energy transfer between scales. Moreover, our experimental device was used to test the limits of the theory developed so far and has led to the development of a new model, which has been validated experimentally and numerically.In addition, we adapted the technique of Laser Induced Fluorescence (LIF) to continuously stratified fluids, with the aim of performing simultaneous measurements of velocity (PIV) and density (LIF). This technique allows us to study experimentally the effect of propagation and destabilization of internal gravity waves on a linear stratification, and to access to quantities related to the mixing
Mujal, i. Colilles Anna. "PIV applications in vortex rings and oscillatory boundary layers." Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/116447.
Full textLa tècnica experimental del Particle Image Velocimetry (PIV) és una de les més utilitzades en el món de la mecànica de fluids per obtenir el camp de velocitats en un flux. La seva no interferència en el desenvolupament del fenomen que s’estudia la fa aplicable a tot tipus de fenòmens, ja sigui micro com macroscòpics i permet estudiar qualitativa i quantitativament la dinàmica de fluids d’un fenomen particular. Aquesta tesis presenta l’aplicació del PIV a dos problemes de mecànica de fluids diferents: anells de vorticitat impactant contorns permeables i capes límit oscil•latòries dins del règim transitori. La primera part d’aquesta tesis es centra en l’estudi dels anells de vorticitat impactant contorns permeables i la seva comparació amb l’impacte del mateix anell amb una paret sòlida. Assumint que un anell de vorticitat és una estructura axisimètrica, s’han realitzat experiments PIV en 2D, en quatre contorns permeables diferents i un contorn sòlid. Quan un anell de vorticitat es mou cap a una superfície sòlida es fan presents tres fenòmens principals: la desacceleració de l’anell de vorticitat quan assoleix una distància amb la paret de l’ordre del diàmetre inicial de l’anell. Al mateix temps un augment del diàmetre produint un efecte estirament i finalment l’aparició d’un segon anell de vorticitat quan el primer anell ha assolit la distància mínima de la paret. El treball experimental aporta algunes conclusions interessants sobre l’evolució d’aquestes característiques principals a mesura que la permeabilitat del contorn d’impacte augmenta: la distància de la paret a la qual comença la desacceleració disminueix, el diàmetre de l’anell de vorticitat primari creix amb menys intensitat i finalment el segon anell de vorticitat és més dèbil i té una vida més curta. La segona i tercera part de la tesis es centren en descriure el fenomen de capa límit oscil•latòria en fluxos sobre llits llisos i rugosos. En aquesta tesis es descriuen els experiments centrats en l’estudi de la capa límit oscil•latòria sobre fons llis i dos tipus diferents de fons rugós per a un rang de Rew = 0.4.104 ~ 2.104; els experiments es centren en la transició de règim laminar a règim laminar a turbulent i utilitzen la tècnica de 2D PIV amb multicàmera aplicada a un túnel de flux oscil•latori. Algunes variables característiques com el gruix de la capa límit o el factor de fricció s’analitzen des de diferents perspectives. Els resultats obtinguts en els experiments de llit rugós coincideixen amb les prediccions realitzades per a teoria existent. Per als experiments en llit rugós diferents formulacions es comparen. Finalment els resultats mostren com la diferència de fase entre la velocitat de paret i a la velocitat del pistó que activa l’oscil•lació es defineix més bé quan es calcula a través de la integral de la quantitat de moviment. Les diferències observades amb els resultats obtinguts quan es calcula a través de la suma de tensions de Reynolds i tensions viscoses són degudes principalment a la sensibilitat d’ambdues equacions a la definició del zero d’ordenades. Per altra banda, el gruix màxim observat per la capa límit es produeix just abans de que es produeixi l’instant de velocitat zero, també anomenat fase del revers, independentment del règim del flux. Finalment es realitza un anàlisi detallat de les estructures presents en les capes límit oscil•latòries definint fins a quatre tipus diferents: tubs de vorticitat presents en fluxos oscil•latoris sobre llits llisos, vòrtexs, bursts i capes de tensió detectades en els fluxos sobre llits rugosos. L’evolució dels tubs de vorticitat coincideix amb la teoria ja publicada i són el resultat de l’aparició de la inestabilitat de Kelvin-Helmholtz. Els experiments descrits en aquesta tesis confirmen les mateixes característiques i permeten definir la vida d’aquests tubs de vorticitat. Les estructures presents en llits rugosos són una mica més complicades degut a que la seva formació i evolució està clarament influenciada per la posició dels grans de sediment que formen el fons. Els vòrtexs es creen darrere una punta en el perfil del llit de sediment durant la fase del revers prop de la paret i es separen d’aquesta quan comença el cicle d’acceleració. L’evolució tant de la posició vertical com horitzontal d’aquests vòrtexs depenen del quocient entre l’amplitud de l’oscil•lació i la rugositat del sediment. Els bursts es defineixen com a aquelles estructures que neixen sent un vòrtex però perden la forma de seguida. De fet, aquests bursts són vòrtexs de mida més petita i que apareixen en localitzacions properes en el camp de velocitats instantani. No obstant quan es realitza la mitjana en fase, la seva forma desapareix, mostrant-se com a bursts. La seva trajectòria és semblant a la dels vòrtexs prèviament descrits, però assoleixen una alçada inferior. Finalment les capes de tensió es visualitzaren només en els experiments portats a terme amb la màxima rugositat i es defineixen com una successió de vòrtexs creats en el mateix gra. Aquestes últimes estructures estan relacionades amb els vòrtexs inicialment descrits ja que aquests es formen amb les estructures romanents de la capa de tensió just quan es produeix el revers del flux. El treball presentat en aquesta tesis es basa en dos problemes de mecànica de fluids. No obstant confirma que la tècnica del PIV és aplicable a fenòmens totalment diferents.
Kunning, Mao. "Strong Authentication Protocol using PIV Card with Mobile Devices." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-128418.
Full textLad, Neetin. "Benchmarking a single-stem PIV endoscope in a spray." Thesis, University of Leicester, 2011. http://hdl.handle.net/2381/10127.
Full textRoclawski, Harald. "PIV Measurements of Channel Flow with Multiple Rib Arrangements." UKnowledge, 2001. http://uknowledge.uky.edu/gradschool_theses/303.
Full textFarrugia, N. "Vector-scalar imaging in combustion using PIV and LIF." Thesis, Cranfield University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309583.
Full textMARTINS, FABIO JESSEN WERNECK DE ALMEIDA. "CHARACTERIZATION OF NEAR-WALL TURBULENT FLOWS BY TOMOGRAPHIC PIV." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=31573@1.
Full textCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE EXCELENCIA ACADEMICA
PROGRAMA DE DOUTORADO SANDUÍCHE NO EXTERIOR
O estudo fundamental de estruturas turbulentas próximas a paredes é de significativa importância devido ao seu papel dominante em inúmeras aplicações de engenharia. Em escoamentos turbulentos, estruturas de diferentes escalas interagem entre si através de um fenômeno complexo caracterizado por um processo contínuo e auto-sustentável. Embora a presença de padrões de movimento coerente pareça ser responsável pela manutenção da turbulência, a evolução e a interação destas estruturas ainda não são completamente entendidas. Para investigar tais fenômenos, foram realizados estudos de escoamentos turbulentos próximos a paredes sobre uma placa plana em um túnel de vento e dentro de um canal de água quadrado. O presente trabalho empregou uma técnica tomográfica de velocimetria por imagem de partícula de alta taxa de medição de campos de velocidade tridimensionais. O processamento da técnica tomo-PIV foi otimizado a fim de melhorar o desempenho do algoritmo e a exatidão dos campos vetoriais medidos. As medições realizadas permitiram a obtenção de estatísticas condicionais das estruturas coerentes típicas da camada limite turbulenta, tais como regiões de baixa e de alta velocidades, varreduras (sweeps), ejeções (ejections) e vórtices. Os resultados quantitativos mostraram vórtices distribuídos por todo o escoamento, entretanto, concentrados na vizinhança das regiões de baixa velocidade e ejeções. Os resultados indicaram que os vórtices estavam indiretamente correlacionados com o processo de produção de turbulência, apesar de serem os principais responsáveis pela dissipação da energia turbulenta.
The fundamental study of turbulent structures near a wall is of significant importance due to its dominant role in innumerous engineering applications. In turbulent flows, eddies of different scales interact with each other in a complex phenomenon of a continuous self-sustaining process. Although the presence of patterns of coherent motion seem to be responsible for the maintenance of turbulence, the evolution and the interaction of these structures are still not completely understood. To investigate such phenomena, near-wall turbulent flows over a smooth at plate in a wind tunnel and inside a square water channel were conducted. The present work employed a high-repetition tomographic PIV technique to measure three dimensional, time-resolved velocity fields. The tomo-PIV processing was optimized in order to improve the algorithm performance and the vector fields accuracy. Conditional statistics of coherent structures, namely, lowand high-speed regions, sweeps, ejections and vortices, were computed. Quantitative results showed vortical structures spread all over the flow, nevertheless, concentrated close to low-speed regions and ejections. Results indicated that vortical structures were indirectly correlated with the process of turbulence production, although they were the main responsible for the turbulent energy dissipation.
L étude fondamentale des structures turbulentes proche d une paroi est d une significative importance en raison de son rôle dominant dans nombreuses applications d ingênierie. Dans les écoulements turbulents, des structures d échelles différentes interagissent dans un phénomène complexe caractérisé par un processus autonome et continu. Bien que la présence de modéles de mouvements cohérents semble entretenir la turbulence, l évolution et l interaction de ces structures ne sont pas encore complétement compris. Pour analyser ces phénomènes, l étude d écoulements turbulents à proximité de paróis a été effectuées sur une plaque plane dans une soufflerie et à l intérieur d un canal hydraulique de section carrée. Une technique tomographique de vélocimétrie par images de particules pour mesurer de champs de vitesse tridimensionnel a été employée. Le traitement des données a été optimisé afin d améliorer la précision des champs de vecteurs mesurés. Les mesures realisés ont permis d obtenir des statistiques conditionnelles des structures cohérentes, à savoir, les régions à faible et à grande vitesse, les sweeps, les ejections et les tourbillons. Les résultats quantitatives ont montré des structures tourbillonnaires distribués sur tout le ux, cependant, concentrée au voisinage des régions à faible vitesse et des ejections. Les rèsultats ont indiqué que les structures tourbillonnaires étaient indirectement corrélés avec le processus de production de la turbulence, bien qu ils ont été les principaux responsables de la dissipation d énergie turbulente.
Gajdušek, Martin. "Bioflavouring piv pomocí studeného chmelení za použití českých chmelů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-449727.
Full textPan, Zhao. "Error Propagation Dynamics of PIV-based Pressure Field Calculation." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6353.
Full textLuna, Flavia Daylane Tavares de. "Estudo de sedimentador contínuo usando fluidodinâmica computacional." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-22052018-142847/.
Full textDue to their operation facility and high efficiency, settlers are widely used by industries for separating components of different densities. The performance of sedimentation, however, depends on the flow field is inside the equipment, which in turn is influenced by the characteristics of the solids in suspension and by the geometry and size of the separation tank. The hydrodynamic characteristics of a vertical circular settler were investigated in the present work by means of both experimental and numeric approaches. The experimental analyses were carried out by particle image velocimetry in a settler prototype built in transparent crystal acrylic. The simulations were carried out using the software ANSYS CFX version 16.0, considering a 3-D, turbulent, isothermal and steady-state flow. The computational fluid dynamics model was used in the progressive approach. The models were initially tested for the one-phase process (water) and checked against the experimental data. Six RANS turbulence models were analyzed: k-epsilon, Renormalization Group (RNG) k- epsilon, k-omega, Shear Stress Transport (SST) and Reynolds Stress models (BSL RSM and SSG RSM). For the two-phase flow, the Euler-Euler multiphase model was used together with the particle model and the Gidaspow model. In this context, several configurations of boundary conditions and modifications in the original tank design were analyzed using vector field, flow lines, volumetric concentration and turbulent kinetic energy. The results showed that the BSL RSM turbulence model was more appropriate to explain the flow in the continuous settler, being able to predict the recirculations and velocity variations along the equipment. The recirculation zones (position and magnitude) were influenced by the boundary conditions and by the geometric shape of the separation tank. It was found that an increase in the diameter of the settler tank (in 40.0%) favored the water and solid separation, increasing its efficiency by 17.3%, while an increase in the height of the tank (in 40.0%) reduced the efficiency of separation by 27.5% when compared to the original design.
Wei, Fei. "Weighted least-squares finite element methods for PIV data assimilation." Thesis, Montana State University, 2011. http://etd.lib.montana.edu/etd/2011/wei/WeiF0811.pdf.
Full textDominguez, Ontiveros Elvis Efren. "Wall-pressure and PIV analysis for microbubble drag reduction investigation." Texas A&M University, 2004. http://hdl.handle.net/1969.1/2582.
Full textCheminet, Adam. "Development of tomographic PIV for the study of turbulent flows." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX020/document.
Full textThis research dissertation focuses on the developments of tomographic PIV (tomo-PIV) for the measurement of turbulent flows (Elsinga et al. 2006). It is based on the tomographic reconstruction of a volumic intensity distribution of tracer particles from projections recorded on cameras. The corresponding volumic distributions are correlated to obtain 3D displacement fields.The present work surveys the state of advancement of the research conducted on this technique and the main issues it has been confronted with so far. The main research focus was on tomographic reconstruction. Indeed, its main limitation is the appearance of ghost particles, ie reconstruction noise, which occurs when high tracer concentrations are required for high spatial resolution measurements.For a thorough understanding of tomographic noise, we carried out a numerical study of experimental factors impacting the quality of tomographic reconstruction. Geometric considerations quantified the impact of "added particles" lying in the Union volume but not in the Intersection volume, between the camera fields of view and the illumination area. This phenomenon was shown to create ghost particles. The decrease in signal-to-noise ratio in the image was investigated, considering Mie scattering and defocusing effects. Particle image defocusing mainly results in the loss of real particles in reconstruction. Mie scattering’s main impact is also the loss of real particles due to the polydisperse nature of the seeding.This study of imaging conditions for tomo-PIV led us to propose an alternative approach to classical tomographic reconstruction. It seeks to recover nearly single voxel particles rather than blobs of extended size using a particle-based representation of image data. We term this approach Particle Volume Reconstruction (PVR). PVR underlies a more physical, sparse volumic representation of point particles, which lives halfway between infinitely small particles, and voxel blobs commonly used in tomo-PIV. From that representation, it is possible to smooth it to 2 voxel diameter blobs for a 3D-PIV use of PVR incorporated in a SMART algorithm. Numerical simulations showed that PVR-SMART outperforms tomo-SMART (Atkinson et al. 2009) on a variety generating conditions and a variety of metrics on volume reconstruction and displacement estimation, especially in the case of seeding density greater than 0.06 ppp.We introduce a cross-correlation technique for 3D-PIV (FOLKI-3D) as an extension to 3D of the FOLKI-PIV algorithm (Champagnat et al. 2011). The displacement is searched as the minimizer of a sum of squared differences, solved iteratively by using volume deformation. Numerical tests confirmed that spatial frequency response is similar to that of standard iterative deformation algorithms. Numerical simulations of tomographic reconstruction characterized the robustness of the algorithm to specific tomographic noise. FOLKI-3D was found more robust to coherent ghosts than standard deformation algorithms, while gains in accuracy of the high-order deformation scheme were obtained for various signal noises.The application of PVR-SMART on experimental data was performed on a turbulent air jet. Several seeding density conditions were used to compare the performance of tomo-SMART and PVR-SMART on the near field region of the jet. With the given image pre-processing, PVR-SMART was found to yield velocity fields that are about 50 % less noisy than tomo-SMART. The velocity field comparison included velocity field statistical properties, peak-locking study, flow divergence analysis, velocity gradient tensor and coherent structures exploration.Finally, conclusions are drawn from the main results of this dissertation and lead to potential research perspectives of our work with respect to the future of tomographic PIV
Comunello, Neodir José. "Estudo de combustão com interação acústica através da técnica PIV." Instituto Tecnológico de Aeronáutica, 2014. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=2951.
Full textVaron, Eliott. "Contrôle réactif d'écoulements décollés à l'aide de PIV temps réel." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLET008/document.
Full textSeparated flows are ubiquitous in nature and industrial systems, such as diffusers, airfoils, air conditioning plants, moving vehicles... As the separation can strongly influence the performances of such devices, investigating their dynamics and their control is of great interest.A visual sensor developed at PMMH laboratory is first improved to measure in real time the velocity fields and its derived values for flows available in wind tunnels. Based on an optical flow algorithm from the computer vision domain, this new experimental approach makes easier parametric studies and may be used in closed-loop controls.The dynamics of the flow over a flat plate are then investigated. A system identification method - the dynamic observer - is successfully implemented to build a reduced-order model of the transient flow, which captures and predicts well the instabilities generated.Finally, the fully turbulent wake of the square-back Ahmed body is described. Dynamical system tools are applied to characterize it. Using continuous and pulsed micro-jets, different forcing strategies are analyzed. An opposition closed-loop control is implemented, tracking and driving the recirculation
Bunjevac, Joseph Antun. "PIV Analysis of Wake Structure of Real Elephant Seal Whiskers." Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu1501102202600591.
Full textGutierrez, Torres Claudia del Carmen. "Modification of turbulent structure in channel flows by microbubble injection close to the wall." Texas A&M University, 2004. http://hdl.handle.net/1969.1/2783.
Full textZhen, Ling. "Wavelet analysis study of microbubble drag reduction in a boundary channel flow." Texas A&M University, 2004. http://hdl.handle.net/1969.1/3200.
Full textHamdi, Jana. "Reconstruction volumique d’un jet impactant une surface fendue à partir de champs cinématiques obtenus par PIV stéréoscopique." Thesis, La Rochelle, 2017. http://www.theses.fr/2017LAROS027/document.
Full textAir conditioning and ventilation systems are often composed of jets having a configuration of an impinging jet, on their end part. Thus, the blown airflows impact slotted obstacles of different shapes to improve mixing. The conditions of confinement and blowing sometimes cause acoustic incompatibility. The acoustic noises generated are due to a phenomenon of feedback loops resulting of the appearance of self-sustained sounds. The production of sound by a free flow or in interaction with a structure has been the subject of many studies. In the case of an acoustic field and for a flow of low Mach number, Howe's energetic correlation is used to evaluate the acoustic power generated or absorbed by the interactions between the acoustic field and the flow. The calculation of this power requires the knowledge of three parameters : vorticity, velocity and acoustic velocity by analytical methods or by using experimental data. Experimentally, the measurement of the kinematic field, to deduce the vorticity, requires a three-dimensional measurement technique. For this purpose, an experimental platform, using laser velocimetry, has been developed and equipped to generate flows of a plane jet. The kinematic fields of these flows were measured using the PIV technique, with a stereoscopic PIV device. The kinematic fields of thirty parallel planes were measured to study the corresponding velocity fields. Two reconstruction methods have been applied to these plans : the POD and the phase average. The volume is obtained by an interpolation of the reconstructed planes giving access to the three components of the velocity. To validate these low-cost 3D reconstruction methods, they were compared to experimental measurements made by the same experimental setup, under the same conditions, by using the tomographic PIV giving access to the three-dimensional kinematic fields
Estrada, Perez Carlos Eduardo. "Analysis, comparison and modification of various Particle Image Velocimetry (PIV) algorithms." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1532.
Full textHenning, James C. "MEASUREMENT OF AIR FLOW VELOCITIES IN MICROSIZED IONIC WIND PUMPS USING PARTICLE IMAGE VELOCEMITRY." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1365424846.
Full textAl-Muhammad, Jafar. "Ecoulement dans un canal millimétrique : étude numérique et expérimentale." Thesis, Ecole centrale de Marseille, 2016. http://www.theses.fr/2016ECDM0013/document.
Full textIn the present context of increasing water scarcity, a better water use efficiency is essential to maintain a sustainable economical growth. Moreover, water use efficiency covers also important environmental and social issues. Micro-irrigation system has the best water efficiency, nevertheless, its use is not much widespread. In the world, this system covers only 3 % of land irrigated against 4% in France, as this system is sensitive to clogging, which increases the installation cost.The baffle-fitted labyrinth-channel is largely used in micro-irrigation systems. The existing baffles, which play an important role for generating pressure losses and ensure the flow regulation on the irrigation network, produce vorticities where the velocity is low or zero. These vorticities favor the deposition of particles or other biochemical development causing emitter clogging. Flow topology characterization in the labyrinth-channel of emitter must be described to analyze emitter clogging sensibility which drastically reduces its performance.Micro-PIV experiments, using 1µm particles, are conducted on ten-pattern repeating baffles to characterize the labyrinth-channel flow and to analyze regions which can be sensitive to clogging. An emitter works with a weak flow rate, and the labyrinth-channel cross-section is about 1 mm2 Reynolds number varies from 400 to 800. So, this experimental investigation allows analyzing the flow regime and its influence. A treatment algorithm is developed to get the mean and fluctuating velocities. Advanced swirl analysis method is adapted to precisely detect the vorticity. Particular attention is focused on the technique acquisition and on pressure losses curves accuracy in the labyrinth-channel flow since this curve represents the emitter global performance.Several turbulent models, implemented in ANSYS/Fluent, are used to perform modelling of the labyrinth-channel geometry. The micro-PIV and modeling results comparisons are presented in order to validate numerical model. The global objective of this manuscript is to identify the best model which allows to predict and analyze the sensitive areas in order to reduce them thanks to geometry optimization
Moutte, Alexandre. "Etude de jets turbulents à masse volumique variable : impact de la variation de masse volumique sur la structure fine et le mélange." Thesis, Ecole centrale de Marseille, 2018. http://www.theses.fr/2018ECDM0003/document.
Full textAn experimental study of the development of turbulent jets with variable density is presented. The axial and radial behaviours of the mean and fluctuating statistical properties obtained on the velocity and concentration fields are analysed. These results provide a better understanding of mixing phenomena and the effect of density variation in order to provide complementary data for the development of numerical calculations and to increase their precision. The cases studied in this thesis are two helium jets carrying acetone vapor for Reynolds numbers Re = 7000 and 11000 to explore the effect of large density variations (S = 0.39 and 0.41, respectively) relative to the ambient air. The case of an air jet (Re = 16000) also carrying acetone vapor is used as a reference case comparable to the case of a passive contaminant with S = 1.17. The study focuses on the region of near jet exit, up to a distance of 40 times the jet outlet diameter Dj. The adopted configuration is a round jet tube, free, axisymmetric, vertical and ascending whose internal diameter of the tube is Dj = 3.5 mm developing in the ambient air. The particularity of this study is the implementation of an optical diagnostic measurement system that allows a spatial and temporal coupling of speed and concentration measurements over a region of the flow of a few cm2. To do this, the coupling of the PIV measurements for the measurement of the velocity field and the PLIF based on the fluorescence of the acetone vapor for the measurement of the concentration field has been studied, designed and tested. It allowed us to obtain a database, still too rare today, on the evolution of the turbulent flow of speed and concentration. These data have shown a faster evolution of the lightest jet. However, the correlation coefficients appear to be identical when the self-similar zone of the jet is reached. An approach based on joint speed-concentration density probabilities has revealed differences in the outer region of the jets, where the intermittent boundary gives its imprint on the properties of the mixture
Howell, Jaron A. "Distribution of Particle Image Velocimetry (PIV) Errors in a Planar Jet." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7004.
Full textSigfrids, Timmy. "Hot wire and PIV studies of transonic turbulent wall-bounded flows." Licentiate thesis, KTH, Mechanics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1577.
Full textThe compressible turbulent boundary layer developing over atwo-dimensional bump which leads to a supersonic pocket with aterminating shock wave has been studied. The measurements havebeen made with hot-wire anemometry and Particle ImageVelocimetry (PIV).
A method to calibrate hot-wire probes in compressible ow hasbeen developed which take into account not only the ow velocitybut also the inuence of the Mach number, stagnation temperatureand uid density. The calibration unit consists of a small jetow facility, where the temperature can be varied. The hot wiresare calibrated in the potential core of the free jet. The jetemanates in a container where the static pressure can becontrolled, and thereby the gas density. The calibration methodwas verfied in the at plate zero pressure gradient turbulentboundary layer in front of the bump at three different Machnumbers, namely 0.3, 0.5 and 0.7. The profiles were alsomeasured at different static pressures in order to see theinuence of varying density. Good agreement between the profilesmeasured at different pressures, as well as with the standardlogarithmic profile was obtained.
The PIV measurements of the boundary layer ow in front ofthe 2D bump showed good agreement with the velocity profilesmeasured with hotwire anemometry. The shock wave boundary layerinteraction was investigated for an inlet Mach number of 0.69.A lambda shock wave was seen on the downstream side of thebump. The velocity on both sides of the shock wave as measuredwith the PIV was in good agreement with theory. The shock wavewas found to cause boundary layer separation, which was seen asa rapid growth of the boundary layer thickness downstream theshock. However, no back ow was seen in the PIV-data, probablybecause the seeding did not give enough particles in theseparated region. The PIV data also showed that the shock wavewas oscillating, i.e. it was moving approximately 5 mm back andforth. This distance corresponds to about five boundary layerthicknesses in terms of the boundary layer upstream theshock.
Descriptors:Fluid mechanics, compressible ow,turbulence, boundary layer, hot-wire anemometry, PIV, shockwave boundary layer interaction, shape factor.
Choi, Hae-Jin. "Kinematics measurements of regular, irregular, and rogue waves by PIV/LDV." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4797.
Full textVernet, Julie. "Detailed study of steady incylinder flow and turbulence using stereo-PIV." Thesis, KTH, Mekanik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-92165.
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