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For a freely evolving granular fluid, the buildup of spatial correlations in density and flow field is described using fluctuating hydrodynamics. The theory for incompressible flows is extended to the general, compressible case, including…

Statistical Mechanics · Physics 2009-10-30 T. P. C. van Noije , M. H. Ernst , R. Brito

High-resolution numerical simulations are utilized to examine isotropic turbulence in a compressible fluid when long wavelength velocity fluctuations approach light speed. Spectral analysis reveals an inertial sub-range of relativistic…

High Energy Astrophysical Phenomena · Physics 2013-01-04 Jonathan Zrake , Andrew MacFadyen

A simple and general formalism for mode coupling by a spatial, temporal or spatiotemporal perturbation in dispersive materials is developed. This formalism can be used for studying various linear and non-linear optical interactions…

Optics · Physics 2015-06-19 Brenda Dana , Lilya Lobachinsky , Alon Bahabad

This paper presents a method for generating a turbulent velocity field that can be used as an input for the temporal simulation in wind excited structure problems. Temporal simulations become necessary when nonlinear behaviour, in the…

Fluid Dynamics · Physics 2023-12-15 Pascal Hémon , Françoise Santi

Direct numerical simulation is used to investigate the decay exponent of isotropic homogeneous turbulence over a range of Reynolds numbers sufficient to display both high and low Re number decay behavior. The initial turbulence is generated…

Fluid Dynamics · Physics 2010-07-29 J. Blair Perot

The relative dispersion process in two-dimensional free convection turbulence is investigated by direct numerical simulation. In the inertial range, the growth of relative separation, $r$, is expected as $<r^2(t)>\propto t^5$ according to…

Chaotic Dynamics · Physics 2009-11-11 Takeshi Ogasawara , Sadayoshi Toh

The normalized turbulent dissipation rate $C_\epsilon$ is studied in decaying and forced turbulence by direct numerical simulations, large-eddy simulations, and closure calculations. A large difference in the values of $C_\epsilon$ is…

Classical Physics · Physics 2007-12-18 Wouter J. T. Bos , L. Shao , Jean-Pierre Bertoglio

An analytical model for the streamwise velocity space-time correlations in turbulent flows is derived and applied to the special case of velocity fluctuations in large wind farms. The model is based on the Kraichnan-Tennekes random sweeping…

Fluid Dynamics · Physics 2023-05-18 Laura J. Lukassen , Richard J. A. M. Stevens , Charles Meneveau , Michael Wilczek

Synthetic models of Eulerian turbulence like so called "Kinematic Simulations" (KS) have been criticized by Thomson & Devenish (TD) (2005), who argued that sweeping decorrelation effects suppress pair dispersion in such models. We derive…

Fluid Dynamics · Physics 2012-08-20 Gregory L. Eyink , Damien Benveniste

It has long been established that turbulent jets comprise large-scale coherent structures, now more commonly referred to as "wavepackets". These structures exhibit a remarkable spatio-temporal organisation, despite turbulence. In this work…

Fluid Dynamics · Physics 2017-09-27 Onofrio Semeraro , Francois Lusseyran , Luc Pastur , Peter Jordan

We propose a new Eulerian turbulence theory to obtain a closed set of equations for homogeneous, isotropic turbulent velocity field correlations and propagator functions by incorporating constraints of random Galilean invariance. This…

Mathematical Physics · Physics 2013-07-10 R. V. R. Pandya

Theoretical modeling of the driving processes of solar-like oscillations is a powerful way of understanding the properties of the convective zones of solar-type stars. In this framework, the description of the temporal correlation between…

Solar and Stellar Astrophysics · Physics 2015-05-20 K. Belkacem , R. Samadi , M. J. Goupil , F. Baudin , D. Salabert , T. Appourchaux

We study the time evolution of velocity and pressure gradients in isotropic turbulence, by quantifying their decorrelation time scales as one follows fluid particles in the flow. The Lagrangian analysis uses data in a public database…

Fluid Dynamics · Physics 2015-05-14 Huidan Yu , Charles Meneveau

In incompressible and periodic statistically stationary turbulence, exchanges of turbulent energy across scales and space are characterised by very intense and intermittent spatio-temporal fluctuations around zero of the time-derivative…

Fluid Dynamics · Physics 2018-08-28 Tatsuya Yasuda , John Christos Vassilicos

We use a data-driven approach to model a three-dimensional turbulent flow using cutting-edge Deep Learning techniques. The deep learning framework incorporates physical constraints on the flow, such as preserving incompressibility and…

Fluid Dynamics · Physics 2021-12-08 Mohammadreza Momenifar , Enmao Diao , Vahid Tarokh , Andrew D. Bragg

We consider the system of equations describing motion of compressible viscoelastic fluids in a whole space. We investigate the large time behavior of solutions around a motionless state, and obtain the $L^p$ decay estimates of solutions for…

Analysis of PDEs · Mathematics 2020-05-05 Yusuke Ishigaki

A phenomenological model for the dissipation of scalar fluctuations due to the straining by the fluid motion is proposed in this letter. An explicit equation is obtained for the time evolution of the probability distribution function of a…

Fluid Dynamics · Physics 2015-06-26 Antoine Venaille , Joel Sommeria

Motivated by specific data and accuracy requirements for building numerical databases of turbulent flows, data compression using spatio-temporal sub-sampling and local re-simulation is proposed. Numerical re-simulation experiments for…

Fluid Dynamics · Physics 2020-07-01 Zhao Wu , Tamer A. Zaki , Charles Meneveau

We have imagined a numerical experiment to explore the onset of turbulent intermittency associated with a spatial perturbation of the correlation length. We place two isotropic regions, with different integral scales, inside a volume where…

Fluid Dynamics · Physics 2012-11-29 Daniela Tordella , Michele Iovieno

Spatiotemporal correlation of magnetic field fluctuations is investigated using the Magnetospheric Multiscale mission in the terrestrial magnetosheath. The first observation of the turbulence propagator in space emerges through analysis of…