Дисертації з теми "Interaction entre les ondes et la turbulence"
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Mohamed, Ahmed. "Nonlinear inertial waves focusing in rotating flows." Electronic Thesis or Diss., Ecully, Ecole centrale de Lyon, 2023. http://www.theses.fr/2023ECDL0058.
We investigate the propagation of inertial waves generated by the oscillation of an axisymmetric torus in a rotating fluid. These inertial waves propagate from the oscillating torus with a propagation angle θf, determined by the dispersion relation. They focus to a focal region where nonlinear interactions may induce turbulence. Our study employs direct numerical simulations to model this flow, considering both linear and nonlinear regimes, and using two torus forcing configurations. The first model simplifies the torus as a local volume force using a Dirac delta function (Dirac ring) along the torus’s oscillation direction in the momentum conservation equations. The second, more realistic model implements a 3D torus using the penalization method. Our findings reveal the emergence of a central vortex as a result of the nonlinear interactions of the propagated inertial waves. In the case of the Dirac ring and the linear regime, our results demonstrate a relationship between vertical kinetic energy and propagation angle at thefocal point, with maximum energy occurring at θf = 35o. Similarly, in the 3D torus forcing scenario, both linear and nonlinear simulations indicate an optimal angle of θf = 30o, leading to maximum vertical velocity and dissipation, signifying efficient energy transfer from the oscillating source to the focal region. In the nonlinear regime, we show the detailed spectral distribution of kinetic energy within the focal zone and conduct spatio-temporal analysis of the velocity field. This analysis identifies triadic resonances of the inertial waves, which drive the generation of a turbulent patch and a large-scale mode similar to the geostrophic mean flow
Crespo, Matthieu. "Etude de l'interaction entre une onde de choc et une turbulence cisaillée en présence de gradients moyens de température et de masse volumique." Thesis, Toulouse, INPT, 2009. http://www.theses.fr/2009INPT039H/document.
This study sheds some light on the effects of a specific sheared flow over the shock / turbulence interaction phenomenon. An efficient and modular computational tool using an oriented object approach has first been developed in order to carry out direct numerical simulations of this configuration. The use of high order shock capturing schemes allows to solve accurately the turbulent flow, even in presence of physical discontinuities. A detailed study concerning the effects of this specific mean shear on the turbulent flow has then been conducted in a shock-free configuration. This preliminary study emphases some significant parameters of this flow configuration. In a second step, DNS of the interaction between the turbulent shear flow and a normal shock ware are performed. These simulations are compared to the isotropic turbulence / shock interaction situation, which allows to underline the activationof specific mechanisms due to the presence of the mean shear in the upstream flow. An interesting database is now available and can be used to assess and improve turbulence models. This is also an interesting point of view for studying the shock/boundary layer interaction phenomenon
Galmiche, Martin. "Interaction turbulence-champs moyens et ondes de gravités internes dans un fluide stratifié." Toulouse, INPT, 1999. http://www.theses.fr/1999INPT017H.
Depommier, Guillaume. "Analyse de l'interaction entre un jet turbulent et un tourbillon." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2010. http://tel.archives-ouvertes.fr/tel-00814804.
Dochy, Thibaut. "Interaction entre ultrasons de puissance et fluides complexes." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30298/document.
The evolution of an initially homogeneous solution consisting of two species subjected to a thermal gradient which generates a mass transfer, which can lead to the separation species from the binary fluid, is studied. The configuration chosen to study the separation is a rectangular (or parallelepipedic) cell, horizontal and placed in the gravitational field. The presence of a piezoelectric source on one of the vertical walls of the cavity makes it possible to generate a stationary flow on a large scale. The flow is induced by the propagation of ultra-sonic waves within the viscous fluid : the dissipation of the acoustic energy of the wave within the fluid is called Eckart streaming. We seek to optimize the separation by combining thermal gradient and acoustic source. The first part consists of the study of the isothermal flow generated by the ultrasonic wave in a monoconstituent fluid. After calculating the acoustic intensity field with the Rayleigh integral, the profile is implemented in a Comsol Multiphysics finite element code. The numerical results are compared with previous experimental results. In a second part, we consider a cavity containing a binary fluid. A configuration heated from the top is privilegied to allow the insertion of an acoustic source. The separation (difference of mass fraction between the two ends of the cell) is determined analytically using the Maple software as a function of the control parameters of the problem. 2D and 3D numerical simulations showed a good agreement between the analytical and numerical results, for a constant acoustic parameter. The problem considered depends on eight dimensionless parameters. Three of them are specific to the nature of the binary fluid : the Lewis number Le, the Prandtl number Pr and the separation factor ψ. There are then two control parameters, the thermal Rayleigh number Ra and the adimensional acoustic force A. Finally, the other dimensionless parameters are the two aspect ratios of the cavity, as well as the relative thickness of the beam
Muraglia, Magali. "Modélisation et simulation de l'interaction multi-échelle entre îlots magnétiques et la microturbulence dans les plasmas de fusion magnétisés." Aix-Marseille 1, 2009. http://www.theses.fr/2009AIX11052.
In a tokamak, it exists many kind of instability at the origin of a dammage of the confinement and worst of a lost of a confinement. This phd presents a study of the dynamics of a magnetic island in presence of turbulence in magnetized plasmas. More precisely, the goal is to understand the multiscales interaction between turbulence, generated by a pressure gradient and the magnetic field curvature, and a magnetic island formed thanks to a tearing mode. Thanks to the derivation of a 2D slab model takking account both tearing and interchange instabilities, theoretical and numerical linear studies show the pressure effect on the magnetic island linear formation and show interchange modes are stabilized in presence of a strong magnetic field. Then, a numerical nonlinear study is presented in order to understand how the interchange mechanism affects the nonlinear dynamics of a magnetic island. It is showned that the pressure gradient and the magnetic field curvature affect strongly the nonlinear evolution of a magnetic island through dynamics bifurcations. The nature of these bifurcations should be characterized in fonction of the linear situation. Finally, the last part of this phd is devoted to the study of the origin of the nonlinear poloidal rotation of the magnetic island. A model giving the different contributions to the rotation is derived. It is showned, thanks to the model and to the numerical studies, that the nonlinear rotation of the island is mainly governed by the E x B poloidal flow and/or by the nonlinear diamagnetic drift
Leconte, Michaël. "Interaction entre écoulements cisailles et transport turbulent dans les plasmas de fusion magnétique." Aix-Marseille 1, 2008. http://www.theses.fr/2008AIX11047.
Queka, Abdulwahab. "Etude expérimentale des régimes instables du système faisceau d'ions-plasma : analyse de la turbulence acoustique ionique." Aix-Marseille 1, 2001. http://www.theses.fr/2001AIX11016.
Moreau, Julien. "Interaction entre un jet et un tourbillon compressé. Etude expérimentale de l'aérodynamique et de mélange." Phd thesis, Institut National Polytechnique de Toulouse - INPT, 2003. http://tel.archives-ouvertes.fr/tel-00007174.
Lagraa, Boualem. "Interaction entre les mouvements à grandes échelles et les structures pariétales dans une couche limite turbulente." Valenciennes, 2002. https://ged.uphf.fr/nuxeo/site/esupversions/84542f6a-fa43-4a55-b554-3c8fa850e79d.
L'objectif de ce travail vise à une meilleure compréhension des mécanismes de la turbulence pariétale. Différentes approches expérimentales sont utilisées, la Vélocimétrie Laser Doppler (VLD), la Vélocimétrie par images de particules (PIV), et la polarographie. Le caractère non intrusif de ces méthodes a permis de préciser le comportement dynamique des structures cohérentes au voisinage de la paroi. La mise en œuvre de l'analyse conditionnelle effectuée sur les différents signaux de vitesse et du frottement, a permis de déterminer l'intensité, l'échelle et la fréquence des différents événements. L'analyse des corrélations spatio-temporelles montre que les tourbillons en épingle à cheveux évoluent par 'paquets' en formant une structure inclinée par rapport à la paroi. Les mesures à l'aide de la PIV confirment ces résultats
Raimbaud, Quentin. "Interaction entre une onde de choc et un film de savon." Thesis, Rennes 1, 2019. http://www.theses.fr/2019REN1S103.
Numerous works have proven that liquid foams significantly attenuate shockwaves. However, even though many theories have been developed, the underlying mechanisms behind this attenuation remains mostly unknown. For the sake of simplicity, we studied the interaction between shockwaves and one of the base elements of foam: foam films. To generate the shockwaves we needed, we created a modular shocktube that allows us to modify both the shape of the pressure signal and the orientation of the films. We started by studying the acceleration of a single foam film impacted by a parallel shockwave. We observed the reflexion and transmission of the shockwave and the movement of the film, which allowed us to get the film’s acceleration time and terminal velocity. We then studied the effects of thickness gradients within the film during the acceleration phase. We developed a model to explain how these gradients affect the breaking of the films. Finally, we studied the interaction between a shockwave and a film, when the two are not parallel to each other. We observed the development of a Kelvin-Helmholtz instability in the film before its rupture
Zarzoso, David. "Description de l'interaction entre les particules energetiques et les ondes dans les plasmas de fusion." Phd thesis, Ecole Polytechnique X, 2012. http://pastel.archives-ouvertes.fr/pastel-00765271.
Michel, Guillaume. "Parois et ondes de surface : dissipation, effet Doppler et interactions non linéaires." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEE038/document.
In this thesis, we study the impact of solid boudaries on surface waves. We first consider the dissipation caused by dynamical wetting. We experimentally show how the damping of surface waves evolves with the size of the meniscus and demonstrate that in perfect wetting it leads to a nonlinear behavior as soon as the meniscus oscillation amplitude compares to the thickness of the boundary layer. Secondly, we investigate energy exchanges through scales occuring when a surface wave reflects on an oscillating wall, the so-called generalized Doppler effect. We evidence the creation of Doppler-shifted waves, compute their amplitudes and illustrate how the continuous bouncing of surface waves on wavemakers may lead to self-similar spectra competing with the ones of wave turbulence. Finally, we focus on nonlinear interaction between surface waves. We prove that gravity waves can undergo triad resonances in confined geometry. Going beyond the consequencies of solid boundaries, we perform experiments on four-wave interactions in the gravity regime and describe large scales in capillary wave turbulence
Moreau, Julien. "Interaction entre un jet et un tourbillon compressé : étude expérimentale de l'aérodynamique et du mélange." Toulouse, INPT, 2003. http://www.theses.fr/2003INPT049H.
Bariki, Chaimae. "Interaction entre une flamme de prémélange et une structure tourbillonnaire." Thesis, Orléans, 2018. http://www.theses.fr/2018ORLE2067.
Understanding and predicting the different mechanisms at play in turbulent premixed flames is a tremendously difficult issue for sizing or optimizing many combustion systems. Turbulent reactive flows are characterized by a complex interaction between the fluid motion, the inherent heat generated by the flame and turbulence. This challenge being extremely difficult to meet, the study of the interactions between a flat flame and a toroidal vortex provide an ideal canonical framework to better understand the physical mechanisms at play. In this perspective, experimental studies were carried out using a stagnation burner fed by a premixed fuel and air (methane/air,propane/air, hydrogen/air). A panel of experimental techniques as well as numerical tools have been used to characterize thoroughly the flame/vortex interactions. By modifying the equivalence ratio, the mixture composition and the vortex intensity, the temporal evolution of the interaction enable the extraction of the flame surface, the flame front stretch and curvature as well as the displacement/consumption speeds. In addition, the internal flame structure is deeply investigated by decomposing the flame front into a preheat zone and a reaction zone
Benrabah, Omar. "Mesure des vitesses en milieu diphasique par velocimetrie laser : interaction entre le mouvement des particules solides et la turbulence." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13108.
Benrabah, Omar. "Mesure des vitesses en milieu diphasique par vélocimétrie laser interaction entre le mouvement des particules solides et la turbulence /." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb376117493.
Silva, Carlos Frederico Neves Bettencourt da. "Le Rôle des structures cohérentes dans le contrôle et interactions entre échelles dans les jets ronds, plans et coaxiaux." Grenoble INPG, 2001. http://www.theses.fr/2001INPG0060.
Fontaine, Alain. "Interaction entre une onde acoustique et un fluide : application à la thermoacoustique et à la séparation des constituants d'un mélange binaire par onde ultrasonore." Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1949/.
In the present work, we study the interaction between an acoustic wave and a compressible and incompressible fluid. In the first part, we present the numerical study of a thermoacoustic refrigerator and more particularly the influence of the gas state equation on the thermoacoustic effect. Thermoacoustic heat pumping is a complex phenomenon which leads to a hydrodynamic heat flux in the thermal boundary layer near a porous medium, due to acoustic waves. The second part deals with the influence of acoustic streaming on species separation of a binary mixture in a shallow cavity cell subjected to temperature gradient and under microgravity. The unicellular flow inducted by the streaming may lead to significant species separation. Analytical results are corroborated by direct numerical simulations. Then, a linear stability analysis of the unicellular flow is performed
Philit, Mickaël. "Modélisation, simulation et analyse des instationnarités en écoulement transsonique décollé en vue d'application à l'aéroélasticité des turbomachines." Thesis, Ecully, Ecole centrale de Lyon, 2013. http://www.theses.fr/2013ECDL0033/document.
In modern turbomachinery design, predicting aerolastic phenomena has become a key point. The development of highly loaded components, while reducing their weight, increases the risk of failure. In this context, good understanding and prediction of various instabilities are a major industrial and scientific challenge. This research work aims to improve the prediction of unsteady phenomena involved in turbomachinery aeroelasticity. This study focuses especially on the simulation of shock wave/boundary layer interaction. To begin with, a transonic nozzle separated flow is investigated. Forced oscillation of the shock wave system is simulated through a small unsteady perturbation method combined with the assumption of variable turbulence. This approach is validated against exprimental measurements. The first harmonic of pressure on the wall of the nozzle is predicted quite satisfactorily. The need to linearize the turbulence model was shown of high importance. Deriving the turbulence model, leads us to investigate the turbulence modeling performed to predict the shockwave/boundary layer interaction. A two equations turbulence model supplemented by a "time-lagged" equation is implemented to capture non-equilibrium effects of turbulence. All achieved results for a nozzle are consistent with theory, but overproduction of turbulent kinetic energy at leading edge makes the model useless for turbomachinery configurations. However, the introduction of an eddy viscosity stress limiter inside a two-equation turbulence model proves to give good results. The derivation method is thus presented on such a model, precisely on Wilcox model proposed in 2008. Finally, the linearization technique is extended to aeroelastic problems. A loose fluid-structure coupling strategy is adopted. The structural oscillation of the blades is considered for eigen-modes but frequency is free to change during coupling resolution. The new approach is based on the building of a meta-model to describe the fluid dynamic behavior in order to solve directly the coupled fluid-structure system. This technique is validated on a standard high subsonic turbine configuration and takes advantage of a reduced computation time
Barillon, Bruno. "Interaction entre un jet gazeux chargé de particules réactives et une surface chaude : application à un procédé de dépôt de couches minces." Vandoeuvre-les-Nancy, INPL, 1996. http://docnum.univ-lorraine.fr/public/INPL_T_1996_BARILLON_B.pdf.
Colin, Muriel. "Modélisation d'un réflectomètre mode X en vue de caractériser les fluctuations de densité et de champ magnétique : applications aux signaux de Tore Supra." Nancy 1, 2001. http://www.theses.fr/2001NAN10181.
This work deals with the interaction between a probing wave and plasma fluctuations. For all probing wave polarization in reflectometry expermiments, this interaction can be described by a Mathieu's equation. In order to check the validity domain of our model we have developed softwares with new numerical schems (both in O-mode and X-mode). After these validations, the ratio of the wave amplitude backscattered by density and magnetic fluctuations has been evaluated, and we have confirmed that the density fluctuations are prominent in most of cases in tokamak expermiments. The accuracy of numerical methods is high enough to simulate the reflectometer experiments. The part of coherent fluctuations in 1D is now well determined and a new connection between the spectrum of the phase variations and the turbulence spectrum has been shown
Hadjadj, Abdellah. "Analyse physique et simulation numérique des écoulements compressibles ; application aux tuyères de propulseurs." Phd thesis, Université de Rouen, 1997. http://tel.archives-ouvertes.fr/tel-00011622.
Ayet, Alex. "Flux de quantité de mouvement à l'interface air-mer : approche théorique du couplage entre turbulence et vagues de vent On the Impact of Long Wind-Waves on Near-Surface Turbulence and Momentum Fluxes, in Boundary-Layer Meteorology volume 174, March 2020 Scalewise return to isotropy in stratified boundary layer flows, in JGR Atmospheres 125 (16), August 2020 Scaling laws for the length scale of energy‐containing eddies in a sheared and thermally stratified atmospheric surface layer, in Geophysical Research Letters 47(23), December 2020." Thesis, Brest, 2020. http://www.theses.fr/2020BRES0038.
Despite numerous works, the causal link between wind and waves is still a controversial subject. This is due, among others, to the multi-scale nature of a realistic ocean surface and to wave breaking, which changes its topology. In this thesis, such problems are studied from a theoretical perspective, using a phenomenological model linking the spectral and averaged properties of wall-bounded turbulence through the geometry attached eddies.The first part of the thesis revisits this phenomenological model by questioning its underlying assumptions and, in particular, reveals inconsistencies in the models used for the energy redistribution between turbulence components (the Rotta model). The phenomenological model is then used to study the coupling between long wind-waves (of order 10m) and turbulence. Results indicate that the deformation of attached eddies, induced by this interaction, could explain some of the variability in momentum fluxes for a given mean wind. Finally, the study of the coupling between turbulence and short breaking waves is approached by defining a roughness sublayer, in which the properties of the attached eddies depend solely on the speed of the dominant breaking fronts for a given wind. These two studies from the basis of a new paradigm to study the multi-scale coupling between the turbulent and wave spectra. This would allow accounting for the influence of environmental parameters on momentum and heat fluxes, and opens new paths both from a theoretical perspective and for the analysis of experimental data