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A high-accuracy time discretization is discussed to numerically solve the nonlinear fractional diffusion equation forced by a space-time white noise. The main purpose of this paper is to improve the temporal convergence rate by modifying…

Numerical Analysis · Mathematics 2021-05-04 Xing Liu

We present a new Eulerian framework for the computation of turbulent compressible multiphase channel flows, specifically to assess turbulence modulation by dispersed particulate matter in dilute concentrations but with significant mass…

Fluid Dynamics · Physics 2025-08-12 Ajay Dhankarghare , Yuval Dagan

We study the properties of homogeneous and isotropic turbulence in higher spatial dimensions through the lens of chaos and predictability using numerical simulations. We employ both direct numerical simulations (DNS) and numerical…

Fluid Dynamics · Physics 2023-06-22 Daniel Clark , Andres Armua , Richard DJG Ho , Arjun Berera

We investigate statistical properties of the passive scalar near boundaries (walls) in random (turbulent) flows assuming weakness of its diffusion. Then at advanced stages of the passive scalar mixing its unmixed residue is concentrated in…

Chaotic Dynamics · Physics 2015-03-13 A. Chernykh , V. Lebedev

A framework for deriving probabilistic data-driven closure models is proposed for coarse-grained numerical simulations of turbulence in statistically stationary state. The approach unites the ideal large-eddy simulation model and data…

Fluid Dynamics · Physics 2025-03-25 Sagy Ephrati

Non-perturbative exact flow equations describe the scale dependence of the effective average action. We present a numerical solution for an approximate form of the flow equation for the potential in a three-dimensional N-component scalar…

High Energy Physics - Theory · Physics 2015-06-26 J. Adams , J. Berges , S. Bornholdt , F. Freire , N. Tetradis , C. Wetterich

For linear and fully non-linear diffusion equations of Bellman-Isaacs type, we introduce a class of approximation schemes based on differencing and interpolation. As opposed to classical numerical methods, these schemes work for general…

Numerical Analysis · Mathematics 2014-05-26 Kristian Debrabant , Espen R. Jakobsen

We propose a new application of random tensor theory to studies of non-linear random flows in many variables. Our focus is on non-linear resonant systems which often emerge as weakly non-linear approximations to problems whose linearized…

Mathematical Physics · Physics 2020-03-12 Stéphane Dartois , Oleg Evnin , Luca Lionni , Vincent Rivasseau , Guillaume Valette

Fluctuations in a fluid are strongly affected by the presence of a macroscopic gradient making them long-ranged and enhancing their amplitude. While small-scale fluctuations exhibit diffusive lifetimes, larger-scale fluctuations live…

This is the first in a series of papers where we study the dynamics of a bubble wall beyond usual approximations, such as the assumptions of spherical bubbles and infinitely thin walls. In this paper, we consider a vacuum phase transition.…

General Relativity and Quantum Cosmology · Physics 2023-06-28 Ariel Mégevand , Federico Agustín Membiela

This is the second paper in a cycle investigating the exact solution of loop equations in decaying turbulence. We perform numerical simulations of the Euler ensemble, suggested in the previous work, as a solution to the loop equations. We…

Fluid Dynamics · Physics 2024-03-04 Alexander Migdal

Direct numerical simulation data show that the variance of the coupling term in passive scalar advection by a random velocity field is smaller than it would be if the velocity and scalar fields were statistically independent. This effect is…

Fluid Dynamics · Physics 2012-07-23 Wouter J. T. Bos , Robert Rubinstein , Le Fang

We examine the statistics of active scalar fluctuations in high-Rayleigh number fingering convection with high-resolution three-dimensional numerical experiments. The one-point distribution of buoyancy fluctuations is found to present…

Fluid Dynamics · Physics 2015-05-18 Jost von Hardenberg , Francesco Paparella

We provide a concise PDE-based proof of anomalous diffusion in the Kraichan model -- a stochastic, white-in-time model of passive scalar turbulence. That is, we show an exponential rate of $L^2$ decay in expectation of a passive scalar…

Mathematical Physics · Physics 2024-06-04 Keefer Rowan

On the basis of the dynamical interpretation of Monte Carlo simulations, we discuss the relation of the equilibrium relaxation time, the susceptibility and the statistical error. We introduce a new quantity called {\it the statistical…

Condensed Matter · Physics 2007-05-23 Macoto Kikuchi , Nobuyasu Ito , Yutaka Okabe

We develop numerical methods for reaction-diffusion systems based on the equations of fluctuating hydrodynamics (FHD). While the FHD formulation is formally described by stochastic partial differential equations (SPDEs), it becomes similar…

Fluid Dynamics · Physics 2018-01-17 Changho Kim , Andy Nonaka , John B. Bell , Alejandro L. Garcia , Aleksandar Donev

The temporal statistics of incompressible fluid velocity and passive scalar fields in developed turbulent conditions is investigated by means of direct numerical simulations along the trajectories of self-propelled point-like probes…

Fluid Dynamics · Physics 2018-05-16 Enrico Calzavarini , Yongxiang X. Huang , François G. Schmitt , Lipo P. Wang

We propose a unified method for the large space-time scaling limit of \emph{linear} collisional kinetic equations in the whole space. The limit is of \emph{fractional} diffusion type for heavy tail equilibria with slow enough decay, and of…

Analysis of PDEs · Mathematics 2023-02-22 Emeric Bouin , Clément Mouhot

Anomalous scaling in the statistics of an active scalar in homogeneous turbulent convection is studied using a dynamical shell model. We extend refined similarity ideas for homogeneous and isotropic turbulence to homogeneous turbulent…

Chaotic Dynamics · Physics 2009-11-13 Emily S. C. Ching , W. C. Cheng

The present works is focused on studying bifurcating solutions in compressible fluid dynamics. On one side, the physics of the problem is thoroughly investigated using high-fidelity simulations of the compressible Navier-Stokes equations…

Numerical Analysis · Mathematics 2022-12-21 Niccolò Tonicello , Andrea Lario , Gianluigi Rozza , Gianmarco Mengaldo