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The present research proposes a new memory-efficient method using diffusion models to inject turbulent inflow conditions into Large Eddy Simulation (LES) and Direct Numerical Simulation (DNS) for various flow problems. A guided diffusion…

The predictive power of mean-field theory is emphasized by comparing theory with simulations under controlled conditions. The recently developed test-field method is used to extract turbulent transport coefficients both in kinematic as well…

Solar and Stellar Astrophysics · Physics 2011-01-04 A. Brandenburg , P. Chatterjee , F. Del Sordo , A. Hubbard , P. J. Käpylä , M. Rheinhardt

We present the results of an experimental and numerical investigation of a turbulent flow over a backward-facing step in a channel. Experimental data are visualized using a Particle Image Velocimetry (PIV) device. As a mathematical model we…

Mathematical Physics · Physics 2007-05-23 T. G. Elizarova , E. V. Shilnikov , R. Weber , J. Hureau

We derive the pressure tensor and the heat flux to accompany the new macroscopic conservation equations that we developed previously in a volume-based kinetic framework for gas flows. This kinetic description allows for expansion or…

Fluid Dynamics · Physics 2007-05-23 S. Kokou Dadzie , Jason M. Reese

Minute amount of long chain flexible polymer dissolved in a turbulent flow can drastically change flow properties, such as reducing the drag and enhancing mixing. One fundamental riddle is how these polymer additives interact with the…

Fluid Dynamics · Physics 2021-02-02 Yi-Bao Zhang , Eberhard Bodenschatz , Haitao Xu , Heng-Dong Xi

In the thermally driven superfluid He-4 turbulence, the counterflow velocity $U_{\rm ns}$ partially decouples the normal and superfluid turbulent velocities. Recently we suggested [J. Low Temp. Phys. 187, 497 (2017)] that this decoupling…

Other Condensed Matter · Physics 2018-07-03 Victor. S. L'vov , Anna Pomyalov

A new 3D transition turbulence model, more accurate and faster than an empirical transition model, is proposed. The model is based on the calculation of the pre-transitional u'v' due to mean flow shear. The present transition model is fully…

Fluid Dynamics · Physics 2015-01-12 R. Vizinho , J. Páscoa , M. Silvestre

Depending on their mechanism of self-propulsion, active particles can exhibit a time-dependent, often periodic, propulsion velocity. The precise propulsion velocity profile determines their mean square displacement and their effective…

Soft Condensed Matter · Physics 2024-05-06 Arnau Jurado Romero , Carles Calero , Rossend Rey

We report a detailed analysis of the energy spectra, second- and high-order structure functions of velocity differences in superfluid $^4$He counterflow turbulence, measured in a wide range of temperatures and heat fluxes. We show that the…

Other Condensed Matter · Physics 2018-12-05 S. Bao , W. Guo , V. S. L'vov , A. Pomyalov

We propose a one-fluid analytical model for a turbulently flowing dilute suspension, based on modified Navier-Stokes equation with a $k$-dependent effective density of suspension, $\rho_ {eff}(k)$, and an additional damping term $\propto…

Chaotic Dynamics · Physics 2007-05-23 Victor S. L'vov , Gijs Ooms , Anna Pomyalov

We present results from a systematic numerical study of structural properties of an unforced, incompressible, homogeneous, and isotropic three-dimensional turbulent fluid with an initial energy spectrum that develops a cascade of kinetic…

Statistical Mechanics · Physics 2009-11-11 Chirag Kalelkar

This work extends the minimum-dissipation model of large-eddy simulation and symmetry-preserving discretization to account for active or passive scalar transport and complex physical mechanisms.This novel scalar-minimum-dissipation model…

Fluid Dynamics · Physics 2025-03-03 Jing Sun , F. Xavier Trias , Roel Verstappen

Scale-space energy density function, $E(\mathbf{x}, \mathbf{r})$, is defined as the derivative of the two-point velocity correlation. The function E describes the turbulent kinetic energy density of scale r at a location x and can be…

Fluid Dynamics · Physics 2021-07-07 S. Arun , A. Sameen , Balaji Srinivasan , Sharath S. Girimaji

The paper is devoted to two-phase flow simulations and investigates the ability of a diffusive interface Cahn-Hilliard Volume-of-Fluid model to capture the dynamics of the air-sea interface at geophysically relevant Reynolds numbers. It…

Diffusion of particles in velocity space undergoing turbulent field was extensively studied in the problem of warm beam relaxation. Under low field intensities the diffusion is described by the Fokker-Planck equation with the diffusion…

Plasma Physics · Physics 2007-05-23 Anatoly Zagorodny , Volodymyr Zasenko , Jan Weiland

In these proceedings, we compute the heavy quark momentum diffusion coefficient using QCD effective kinetic theory for a plasma going through the bottom-up thermalization scenario until approximate hydrodynamization. This transport…

High Energy Physics - Phenomenology · Physics 2025-06-25 Kirill Boguslavski , Aleksi Kurkela , Tuomas Lappi , Florian Lindenbauer , Jarkko Peuron

We investigate the statistical properties, based on numerical simulations and analytical calculations, of a recently proposed stochastic model for the velocity field of an incompressible, homogeneous, isotropic and fully developed turbulent…

Fluid Dynamics · Physics 2016-04-28 Rodrigo M. Pereira , Christophe Garban , Laurent Chevillard

We provide a rigorous justification of various kinetic regimes exhibited by the nonlinear Schr\"{o}dinger equation with an additive stochastic forcing and a viscous dissipation. The importance of such damped-driven models stems from their…

Analysis of PDEs · Mathematics 2026-02-19 Ricardo Grande , Zaher Hani

The turbulent flow of a fluid carrying trace amounts of a condensable species through a differentially cooled vertical channel geometry is simulated using single-phase direct numerical simulations. The release of latent heat during…

Fluid Dynamics · Physics 2020-01-28 Philipp Bahavar , Claus Wagner

The present work studied various models for predicting turbulence in the problem of injecting a fluid microjet into the boundary layer of a turbulent flow. For this purpose, the one-equation Spalart-Allmaras (SA), two-equation k-$\epsilon$…