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Book CASCADE INVERSE ET DISPERSION TURBULENTE EN TURBULENCE BIDIMENSIONNELLE

Download or read book CASCADE INVERSE ET DISPERSION TURBULENTE EN TURBULENCE BIDIMENSIONNELLE written by PASCAL.. LE ROY and published by . This book was released on 1988 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: CETTE THESE ETUDIE LA TURBULENCE BIDIMENSIONNELLE AU MOYEN DE SIMULATIONS NUMERIQUES. LA TURBULENCE BIDIMENSIONNELLE INTERESSE SURTOUT LES METEOROLOGUES ET LES OCEANOGRAPHES CAR ELLE CONSTITUE UNE PREMIERE APPROXIMATION DE LEURS ECOULEMENTS. MON TRAVAIL SUR LE MODELE DE TURBULENCE BIDIMENSIONNELLE DU LABORATOIRE DE METEOROLOGIE DYNAMIQUE A CONSISTE A LA FOIS EN L'AMELIORATION DU MODELE ET LA REALISATION DE DIVERSES EXPERIENCES SUR CE MODELE. LA PRINCIPALE AMELIORATION APPORTEE AU MODELE EST LA MISE AU POINT D'UNE BONNE MODELISATION DE LA CASCADE INVERSE D'ENERGIE, I.E. UNE SIMULATION PLUS REALISTE DES PLUS GRANDES ECHELLES DE L'ECOULEMENT. LES EXPERIENCES REALISEES SUR CE MODELE AMELIORE CONCERNENT LA DISPERSION (ABSOLUE OU RELATIVE), I.E. NOUS SIMULONS L'ADVECTION DE FLOTTEURS LAGRANGIENS PAR L'ECOULEMENT. LES RESULTATS OBTENUS DIFFERENT SENSIBLEMENT DES CONJECTURES THEORIQUES ET NOUS OBLIGENT A ENVISAGER UNE APPROCHE DIFFERENTE DE LA DISPERSION TURBULENTE. J'AI AJOUTE LE TRAVAIL D'UNE ANNEE, REALISE COMME SCIENTIFIQUE DU CONTINGENT A L'INSTITUT DE MECANIQUE DE GRENOBLE, SUR LES INSTABILITES QUI SE DEVELOPPENT DANS UNE COUCHE DE MELANGE BIDIMENSIONNELLE

Book TURBULENCE BIDIMENSIONNELLE ET DISPERSION TURBULENTE

Download or read book TURBULENCE BIDIMENSIONNELLE ET DISPERSION TURBULENTE written by JEROME.. PARET and published by . This book was released on 1999 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: NOUS PRESENTONS UNE ETUDE EXPERIMENTALE APPROFONDIE DE LA TURBULENCE BIDIMENSIONNELLE ENTRETENUE. LES EXPERIENCES SONT REALISEES DANS DE MINCES COUCHES DE FLUIDES STRATIFIEES ET LES CHAMPS DE VITESSE SONT DETERMINES A L'AIDE D'UNE TECHNIQUE DE VELOCIMETRIE PAR SUIVI DE PARTICULES. LES CONJECTURES DE KRAICHNAN SUR LA CASCADE INVERSE D'ENERGIE ET LA CASCADE DIRECTE D'ENSTROPHIE SONT CONFIRMEES, NOTAMMENT LES LOIS DE PUISSANCE POUR LES SPECTRES D'ENERGIE. NOUS ETUDIONS LA CASCADE INVERSE DE MANIERE PLUS DETAILLEE. NOUS TROUVONS QUE, EN FONCTION DE LA DISSIPATION D'ENERGIE AUX GRANDES ECHELLES, LE REGIME DE CASCADE INVERSE CLASSIQUE OU LE REGIME CONDENSE SONT OBTENUS COMME ETATS STATISTIQUEMENT STATIONNAIRES. LES PROPRIETES STATISTIQUES DES TOURBILLONS COHERENTS TENDENT A MONTRER QUE LA DYNAMIQUE DE LA CASCADE EST REGIE PAR UN MECANISME D'AGREGATION DES TOURBILLONS DE MEME SIGNE PLUTOT QUE PAR UNE SUCCESSION DE FUSIONS CREANT DES TOURBILLONS DE TAILLE DE PLUS EN PLUS GRANDE. DE PLUS, EN NET CONTRASTE PAR RAPPORT AU CAS TRIDIMENSIONNEL, NOUS TROUVONS QUE LA CASCADE D'ENERGIE NE PRESENTE PAS D'INTERMITTENCE, AVEC DES STATISTIQUES QUASIMENT GAUSSIENNES ET DES EXPOSANTS DE FONCTIONS DE STRUCTURES INDISCERNABLES DES VALEURS DE KOLMOGOROV. CE COMPORTEMENT NON INTERMITTENT EST EGALEMENT OBSERVE POUR LA CASCADE D'ENSTROPHIE. NOUS ETUDIONS LA DISPERSION RELATIVE DE PAIRES DE PARTICULES PASSIVES DANS DES ECOULEMENTS PRESENTANT UNE CASCADE INVERSE D'ENERGIE. LES PROPRIETES STATISTIQUES DE CE PROCESSUS SONT DETERMINEES EN INTEGRANT NUMERIQUEMENT LES TRAJECTOIRES LAGRANGIENNES DES PARTICULES A PARTIR DES CHAMPS DE VITESSE EXPERIMENTAUX. LA LOI HYPERDIFFUSIVE DE RICHARDSON EST OBSERVEE ET UN COMPORTEMENT FORTEMENT NON-GAUSSIEN EST OBTENU POUR LES DISTRIBUTIONS DES SEPARATIONS DES PAIRES. NOUS MONTRONS QUE LE PROCESSUS EST TEMPORELLEMENT AUTO-SIMILAIRE ET QUE DE FORTES CORRELATIONS TEMPORELLES SONT PRESENTES. CES OBSERVATIONS COMPROMETTENT L'APPROCHE EN TERME DE VOLS DE LEVY.

Book DISPERSION LAGRANGIENNE EN TURBULENCE BIDIMENSIONNELLE

Download or read book DISPERSION LAGRANGIENNE EN TURBULENCE BIDIMENSIONNELLE written by NAJET.. ZOUARI and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: UN CHAMP DE TURBULENCE BIDIMENSIONNELLE EST CARACTERISE PAR TROIS ELEMENTS DE BASE: LES STRUCTURES COHERENTES OU LA ROTATION DOMINE, UN PREMARECAGE TURBULENT A LA PERIPHERIE DES TOURBILLONS QUI EST DOMINE PAR LES DEFORMATIONS ET, ENFIN, UN MARECAGE CONSTITUE PAR LE MILIEU RESIDUEL ENTRE LES TOURBILLONS OU LA ROTATION EQUILIBRE LA DEFORMATION. DANS LE CADRE DE CETTE TOPOGRAPHIE NOUS ETUDIONS LES COMPORTEMENTS STATISTIQUES DE LA DISPERSION LAGRANGIENNE AUX DIFFERENTES ECHELLES D'ESPACE ET DE TEMPS EN CONSIDERANT DEUX POINTS ESSENTIELS: I) LES LIMITES DE TOLERANCE DES APPROCHES PUREMENT EULERIENNES; II) LES OUVERTURES FAVORISEES PAR LES ANALYSES LAGRANGIENNES. NOUS PROPOSONS UNE MODELISATION QUI PERMET DE CARTOGRAPHIER LA VALEUR ASYMPTOTIQUE A GRANDE ECHELLE DU COEFFICIENT DE DISPERSION ABSOLUE DANS LE CAS NON HOMOGENE ET QUI COMPLETE CELLE DEJA EXISTANTE DANS LE CAS HOMOGENE 2-D. LA DISPERSION RELATIVE DANS LES CASCADES D'ENSTROPHIE ET D'ENERGIE EST ENSUITE ETUDIEE ANALYTIQUEMENT ET A L'AIDE DES EXPERIENCES NUMERIQUES. NOUS NOUS INTERESSONS EN PARTICULIER A SES COMPORTEMENTS STATISTIQUES DANS LE DOMAINE INERTIEL DE LA CASCADE D'ENERGIE ET ANALYSONS LES CONDITIONS D'OBSERVATIONS DE LA LOI AUTO-SIMILAIRE DE RICHARDSON. NOUS MONTRONS QU'IL EXISTE DES ZONES PRIVILEGIEES D'AFFLUENCE PARTICULAIRE AU SEIN DESQUELLES LES PREDICTIONS AUTO-SIMILAIRES SONT MIEUX VERIFIEES ET QUI SONT DES SIEGES DE MECANISME DE CASCADE INVERSE. NOUS PROPOSONS, ENFIN, UNE NOUVELLE FORMULATION DE LA LOI DE RICHARDSON DANS LA CASCADE D'ENERGIE D'UNE TURBULENCE BIDIMENSIONNELLE

Book DISPERSION DE TRACEURS PASSIFS DANS DES EXPERIENCES DE TURBULENCE BIDIMENSIONNELLE

Download or read book DISPERSION DE TRACEURS PASSIFS DANS DES EXPERIENCES DE TURBULENCE BIDIMENSIONNELLE written by MARIE-CAROLINE.. JULLIEN and published by . This book was released on 2000 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: NOUS PRESENTONS DES RESULTATS EXPERIMENTAUX CONCERNANT LA DISPERSION DE TRACEURS PASSIFS DANS DES EXPERIENCES DE TURBULENCE BIDIMENSIONNELLE ENTRETENUE. LES EXPERIENCES SONT REALISEES POUR DES ECOULEMENTS FORCES ELECTROMAGNETIQUEMENT DANS DE MINCES COUCHES DE FLUIDES STRATIFIEES DE FACON STABLE. LES CHAMPS DE VITESSE SONT ANALYSES A L'AIDE D'UNE TECHNIQUE DE VELOCIMETRIE. DANS UNE PREMIERE APPROCHE, NOUS FAISONS UNE ANALYSE STATISTIQUE DE LA DISPERSION D'UNE TACHE DE FLUORESCEINE, SUCCESSIVEMENT DANS LA CASCADE DIRECTE D'ENSTROPHIE ET DANS LA CASCADE INVERSE D'ENERGIE, CONFORMEMENT AUX CONJECTURES FORMULEES PAR KRAICHNAN EN 1967 A PROPOS DU MECANISME DE DOUBLE CASCADE EN TURBULENCE BIDIMENSIONNELLE. DANS LA CASCADE D'ENSTROPHIE, NOUS MONTRONS QUE LE SPECTRE DES FLUCTUATIONS DE CONCENTRATION SUIT LA LOI DE BATCHELOR EN K - 1, ET QUE LES SOLUTIONS ANALYTIQUES FORMULEES PAR CHERTKOV ET AL. SONT EN TRES BON ACCORD AVEC NOS EXPERIENCES : AILES EXPONENTIELLES POUR LES DISTRIBUTIONS DE FLUCTUATIONS AINSI QUE DE SES INCREMENTS, LOI LOGARITHMIQUE POUR LA FONCTION DE STRUCTURE D'ORDRE 2. DANS LA CASCADE INVERSE, NOUS MONTRONS QUE LA STATISTIQUE D'ORDRE 2 EST BIEN DECRITE PAR LE FORMALISME DE CORRSIN-OBUKHOV. L'ANALYSE DES MOMENTS D'ORDRES PLUS ELEVES REVELE EN REVANCHE UNE SATURATION DES EXPOSANTS DE FONCTION DE STRUCTURE VERS UNE VALEUR CONSTANTE. UNE SECONDE APPROCHE EST UNE APPROCHE LAGRANGIENNE. ELLE CONSISTE A SUIVRE DES PAIRES DE PARTICULES LE LONG DE LEUR TRAJECTOIRES, DETERMINEES EN INTEGRANT NUMERIQUEMENT LES CHAMPS DE VITESSE EXPERIMENTAUX. CETTE ETUDE A ETE REALISEE DANS LA CASCADE INVERSE D'ENERGIE. LA LOI HYPERDIFFUSIVE DE RICHARDSON R 2 T 3 EST OBSERVEE ET UN COMPORTEMENT FORTEMENT NON-GAUSSIEN EST OBTENU POUR LES DISTRIBUTIONS DES SEPARATIONS DES PAIRES. LE PROCESSUS EST TEMPORELLEMENT AUTO-SIMILAIRE ET DE FORTES CORRELATIONS TEMPORELLES SONT PRESENTES.

Book Turbulence  Edition 2013

    Book Details:
  • Author : Marcel Lesieur
  • Publisher : EDP Sciences
  • Release : 2023-11-13T00:00:00+01:00
  • ISBN : 2759833852
  • Pages : 359 pages

Download or read book Turbulence Edition 2013 written by Marcel Lesieur and published by EDP Sciences. This book was released on 2023-11-13T00:00:00+01:00 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence est un livre d’initiation au monde fascinant de la turbulence dans les fluides au sens général : l’eau des rivières et des océans, l’air dans le sillage des véhicules aériens ou terrestres, les granulations solaires, la tache rouge de Jupiter... On y rencontre aussi bien l’imprévisibilité introduite par Henri Poincaré que l’effet papillon du météorologue Edouard Lorenz. Le lecteur comprendra mieux la trainée aérodynamique et la diffusion des polluants dans l’environnement, ou encore les instabilités qui dégénèrent en tourbillons cohérents. Les résultats récents sont présentés et l’auteur propose même des apports sur les écoulements des fluides biologiques ou sur le défi de la turbulence pour les modèles météorologiques et climatiques.L’objectif de l’ouvrage est de faire comprendre les concepts et de présenter des résultats sans équations dans un domaine où il est aisé de remplir un livre de formules mathématiques. L’accent est mis fortement sur les résultats de simulations numériques. Malgré la difficulté du sujet, le style clair et précis permet une lecture agréable et on se surprend à réfléchir sur le concept de turbulence en biologie, histoire et philosophie.Ce livre s’adresse à un public scientifique de niveau master (en mécanique, physique, mathématiques) et bien sûr aux universitaires, chercheurs, enseignants et au public cultivé de ce niveau.Polytechnicien, Marcel Lesieur est professeur émérite de Grenoble Institut National Polytechnique. Il a créé un groupe pionnier dans l’utilisation du calcul scientifique pour la modélisation et la simulation de la turbulence. Auteur de multiples publications, il a oeuvré dans les grands laboratoires mondiaux, à l’USC Los Angeles, Stanford, au NCAR Boulder du Colorado... Membre senior de l’Institut Universitaire de France puis membre de l’Académie des sciences, il offre dans cet ouvrage un aperçu de sa passion pour la turbulence et nous fait bénéficier de ses grandes qualités pédagogiques.

Book Turbulent Cascades II

Download or read book Turbulent Cascades II written by Mikhael Gorokhovski and published by Springer. This book was released on 2019-05-21 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gathering contributions by the most prominent researchers in a highly specialised field, this proceedings volume clarifies selected aspects of the physics of turbulent cascades and their statistical universalities under complex stationary and non-homogeneous conditions. Here, these conditions are induced by the presence of a gas/liquid interface, inertial particles, strong shear, rotation, MHD and stratification. By proposing different ways to model turbulence effects under these complex conditions, the book will be of considerable interest not only to academic researchers, but also to specialists and junior researchers in the domain of propulsion and power, as well as those whose work involves various applications related to atmospheric, oceanic and planetary physics.

Book Turbulence bidimensionnelle

Download or read book Turbulence bidimensionnelle written by René Moreau and published by . This book was released on 1983 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book On the Efficiency of the Turbulent Cascade

Download or read book On the Efficiency of the Turbulent Cascade written by Joseph James Gilles Ballouz and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent flows are chaotic and highly fluctuating, with a large number of interacting scales of motion, which makes them difficult to predict. One approach (known as Large Eddy Simulation) is to resolve all scales of motion down to a cutoff scale of interest and to capture the effect of all omitted smaller scales by modeling the unclosed unresolved turbulent deviatoric stress. This stress appears in the energy equation of the resolved scales of motion in the scale-to-scale energy flux term. The energy flux term is a dot product of two symmetric tensors: the unresolved turbulent stress tensor and the resolved strain rate tensor. Thus, we may interpret it as mechanical work done by the large resolved scales of motion on the smaller unresolved ones. This work is not only a function of the magnitudes of these two tensors but also of the relative alignment of their eigenframes. For no work can be done when the direction of force (stress) is orthogonal to the displacement (strain). A new quantity that characterizes this alignment is the cascade efficiency. Although one of the defining characteristics of the turbulent cascade is the scale-to-scale energy transfer, this transfer is found to be on average inefficient in the inertial range (around 25\%) due to a poor alignment between the stress and strain rate tensors. Another finding is that the embedding dimension of the flow plays a strong role in setting the direction of the scale-to-scale energy flux, for when geometric alignments between the stress and strain rate tensors encountered in three-dimensional turbulence are projected onto a two-dimensional configuration, the direct energy cascade towards smaller scales of motion reverses to a two-dimensional inverse energy cascade towards larger scales. The efficiency proves to be an effective metric in revealing the broken time-reversal symmetry of the turbulent cascade, for it is seen that the geometry of the turbulent stress lags that of the strain rate in three-dimensional turbulence, which is the opposite of what is observed in two dimensions. However, the time lags required for peak alignment do not properly scale with filter size when considering Eulerian quantities lagged in-place or along particle trajectories. It is only when expressing the scale-to-scale energy flux in a fully Lagrangian manner based on the right Cauchy-Green strain rate tensor and the second Piola--Kirchhoff stress tensor, that the times required for peak efficiency along fluid eddies follow the expected 2/3 Kolmogorov scaling.

Book Chaos  Kinetics and Nonlinear Dynamics in Fluids and Plasmas

Download or read book Chaos Kinetics and Nonlinear Dynamics in Fluids and Plasmas written by Sadruddin Benkadda and published by Springer Science & Business Media. This book was released on 1998-07-16 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last few years it has become apparent that fluid turbulence shares many common features with plasma turbulence, such as coherent structures and self-organization phenomena, passive scalar transport and anomalous diffusion. This book gathers very high level, current papers on these subjects. It is intended for scientists and researchers, lecturers and graduate students because of the review style of the papers.

Book Cascades  Spectra  Real Space Structure  Inhomogeneous Mixing and Transport in Active Scalar Turbulence

Download or read book Cascades Spectra Real Space Structure Inhomogeneous Mixing and Transport in Active Scalar Turbulence written by Xiang Fan and published by . This book was released on 2019 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: An active scalar system refers to a system with a scalar field that is coupled to the fluid dynamics and gives feedback to the velocity field through local forces. Active scalar turbulence systems are ubiquitous, and the study of these systems is a central focus of research in theoretical plasma physics. As examples, the 2D Cahn-Hilliard Navier-Stokes (CHNS) system and 2D Magnetohydrodynamics (MHD) system are studied in this dissertation. The similarities and differences between 2D CHNS and 2D MHD are discussed. These are both elastic (i.e., self-restoring) systems, and display a memory, governed by freezing-in laws. The CHNS system supports an elastic wave, which is analogous to Alfven wave in MHD. Cascades and spectra in 2D CHNS are investigated, with focus on the interaction between inverse and forward cascades. The inverse cascade of mean square concentration $\langle\psi^2\rangle$, which is closely related to the real space dynamics of blob formation and merger, is found to be the dominant nonlinear transfer process. The spectrum of $\langle\psi^2\rangle_k$ exhibits a scaling law of $\sim k^{-7/3}$, and this exponent is the same as the corresponding one in 2D MHD. On the other hand, the kinetic energy spectrum follows $E_k\sim k^{-3}$. This exponent is closer to that for 2D Navier-Stokes, instead of that for 2D MHD. We suggest this is because the restoring force is significant only in the interfacial regions. The packing fraction of interfacial regions is small because of the formation and merger of blobs. This suggests that the inverse cascade of $\langle \psi^2 \rangle$--related to blob coalescence--modifies the forward cascade in 2D CHNS. The evolution of the concentration field of the Cahn-Hilliard system in the background of a single eddy is studied. This is analogous to the flux expulsion phenomenon in 2D MHD. Though the system is simple, complex evolution is observed. 3 stages are observed: the “jelly roll” pattern stage, the stage of topological evolution, and the “target” pattern stage. The target pattern is metastable, as the bands gradually merge with time. We also study turbulent transport in active scalar systems. We intended to first explore the classic problem of the suppression of turbulent transport in 2D MHD as an exercise in code verification, and then move to 2D CHNS. However, novel blob-and-barrier real space structures were observed with higher magnetic Reynolds number $\mathrm{Rm}$ in 2D MHD. We argue that the conventional approach of mean field theory is not applicable for the case without an external large scale magnetic field. The magnetic energy is observed to be concentrated in the intermittent, thin transport barrier regions, which located in the interstices between blobs of magnetic potential. The turbulent transport is quenched primarily because of these barriers. Barrier formation is linked to the inverse cascade of mean square magnetic potential $\langle A^2\rangle$ and negative turbulent resistivity. For small scale forcing, spontaneous formation of layering occurs. More generally, we demonstrate that synergistic studies of related but different systems--2D CHNS and 2D MHD--can lead to improved understanding. These studies can provide insights for all active scalar turbulence systems, since these systems share important common properties such as memory, elastic waves, and conservation laws.

Book An Informal Conceptual Introduction to Turbulence

Download or read book An Informal Conceptual Introduction to Turbulence written by Arkady Tsinober and published by Springer Science & Business Media. This book was released on 2009-08-29 with total page 475 pages. Available in PDF, EPUB and Kindle. Book excerpt: This fully revised second edition focuses on physical phenomena and observations in turbulence, and is focused on reversing misconceptions and ill-defined concepts. New topics include ergodicity, Eulerian versus Lagrangian descriptions, theory validation, and anomalous scaling.

Book Impact of Deep Oceanic Processes on Circulation and Climate Variability  Examples from the Mediterranean Sea and the Global Ocean

Download or read book Impact of Deep Oceanic Processes on Circulation and Climate Variability Examples from the Mediterranean Sea and the Global Ocean written by Vincenzo Artale and published by Frontiers Media SA. This book was released on 2022-02-03 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Helical Inverse Cascade in Three dimensional Turbulence as a Fundamental Dominant Mechanism in Mesoscale Atmosheric Phenomena

Download or read book Helical Inverse Cascade in Three dimensional Turbulence as a Fundamental Dominant Mechanism in Mesoscale Atmosheric Phenomena written by Efim Mihajlovič Levič and published by . This book was released on 1985 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Dynamique de la Turbulence Partiellement 2D

Download or read book Dynamique de la Turbulence Partiellement 2D written by Nathaniel T. Baker and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis aims at clarifying the role of the solenoidal component of the Lorentz force in fixing the topological dimensionality, and the ensuing dynamics of low-Rm MHD turbulent flows confined between electrically insulating and no-slip Hartmann walls. The work presented here breaks down into two main parts: An analytical investigation carried out in the weakly inertial limit on the one hand, and an experimental study of fully developed turbulence on the other hand. The analytical investigation was performed on a single steady and axisymmetric electrically driven vortex confined between no-slip and electrically insulating walls perpendicular to a uniform magnetic field. Thanks to an asymptotic expansion valid for any Hartmann number, we showed that the topological dimensionality of the leading order is fully imposed by a single parameter, which compares the distance over which the Lorentz force is able to act in the direction of the magnetic field, before it is balanced out by viscous friction. This study highlights two inertial mechanisms capable of introducing a third velocity component in the direction of the field, by means of recirculations in the meridional plane: direct and/or inverse Ekman pumping. An experimental platform was designed and built from the ground up during this project, to investigate the dynamics of liquid metal turbulence subject to extreme magnetic fields. The turbulence sustained in our experiment was forced electrically by imposing a DC current through a square periodic array of electrodes. Thanks to this setup, we showed that the statistics of the turbulent fluctuations were homogeneous and axisymmetric to a satisfactory level, despite the forcing mechanism being inhomogeneous and anisotropic. By comparing the energy densities measured along the walls perpendicular to the magnetic field, we confirm that the physical processes at stake in the 3D inertial range of wall-bounded MHD turbulence at low-Rm are the solenoidal component of the Lorentz force on the one hand, and inertia on the other hand. Thanks to a statistical analysis in scale space, we show that their exists a universal law imposing the kinematics of turbulent structures in our experiment, which turns out to be fully described by only two lenghtscales. First, the forcing scale in the direction perpendicular to the magnetic field. Second, the range of action of the Lorentz force before it is balanced out by inertial transfers, in the direction parallel to the field. We prove that the ratio of this latter scale over the height of the channel in fact segregates kinematically quasi-2D from kinematically 3D turbulent structures. By computing the actual flux of perpendicular turbulent kinetic energy along perpendicular scales, we show that it always flows towards larger turbulent scales regardless of their topology. In other words, we show that the existence of an inverse cascade of perpendicular kinetic energy does not necessarily require perpendicular turbulent scales to be topologically quasi-2D in the inertial range.

Book Nonlinear Processes in Geophysics

Download or read book Nonlinear Processes in Geophysics written by and published by . This book was released on 2007 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Helical Inverse Cascade in Three dimensional Turbulence as a Fundamental Dominant Mechanisms in Mesoscale Atmospheric Phenomena

Download or read book Helical Inverse Cascade in Three dimensional Turbulence as a Fundamental Dominant Mechanisms in Mesoscale Atmospheric Phenomena written by E. Levich and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Turbulence Cascade in an Inhomogeneous Turbulent Flow

Download or read book Turbulence Cascade in an Inhomogeneous Turbulent Flow written by Felipe Alves Portela and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: