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Particulate flows have been largely studied under the simplifying assumptions of one-way coupling regime where the disperse phase do not react-back on the carrier fluid. In the context of turbulent flows, many non trivial phenomena such as…

Chaotic Dynamics · Physics 2023-07-19 P. Gualtieri , F. Picano , G. Sardina , C. M. Casciola

In a recent article the authors showed that the radiative Transfer equations with multiple frequencies and scattering can be formulated as a nonlinear integral system. In the present article, the formulation is extended to handle reflective…

Numerical Analysis · Mathematics 2023-06-12 Olivier Pironneau , Pierre-Henri Tournier

We propose a novel projection-based particle method for solving the McKean-Vlasov stochastic differential equations. Our approach is based on a projection-type estimation of the marginal density of the solution in each time step. The…

Numerical Analysis · Mathematics 2018-08-07 Denis Belomestny , John Schoenmakers

Markov Chain Monte Carlo (MCMC) algorithms are often used for approximate inference inside learning, but their slow mixing can be difficult to diagnose and the approximations can seriously degrade learning. To alleviate these issues, we…

Machine Learning · Computer Science 2015-02-25 Jacob Steinhardt , Percy Liang

The compressed sensing (CS) framework leverages the sparsity of MR images to reconstruct from undersampled acquisitions. CS reconstructions involve one or more regularization parameters that weigh sparsity in transform domains against…

We formulate and test a hybrid fluid-Monte Carlo scheme for the treatment of elastic collisions in gases and plasmas. While our primary focus and demonstrations of applicability are for moderately collisional plasmas, as described by the…

Computational Physics · Physics 2015-06-12 L. F. Ricketson , M. S. Rosin , R. E. Caflisch , Andris M. Dimits

We present an overview of the Velocity Coordinate Spectrum (VCS), a new technique for studying astrophysical turbulence that utilizes the line-of-sight statistics of Doppler-broadened spectral lines. We consider the retrieval of turbulence…

Astrophysics of Galaxies · Physics 2009-02-03 D. Pogosyan , A. Lazarian

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

Modelling random dynamical systems in continuous time, diffusion processes are a powerful tool in many areas of science. Model parameters can be estimated from time-discretely observed processes using Markov chain Monte Carlo (MCMC) methods…

Computation · Statistics 2020-10-12 Susanne Pieschner , Christiane Fuchs

Modern compression methods can summarize a target distribution $\mathbb{P}$ more succinctly than i.i.d. sampling but require access to a low-bias input sequence like a Markov chain converging quickly to $\mathbb{P}$. We introduce a new…

Machine Learning · Statistics 2024-08-02 Lingxiao Li , Raaz Dwivedi , Lester Mackey

We derive and analyze a broad class of finite element methods for numerically simulating the stationary, low Reynolds number flow of concentrated mixtures of several distinct chemical species in a common thermodynamic phase. The underlying…

Numerical Analysis · Mathematics 2025-09-24 Aaron Baier-Reinio , Patrick E. Farrell

The Linear Smoothing (LS) scheme \cite{francisa.ortiz-bernardin2017} ameliorates linear and quadratic approximations over convex polytopes by employing a three-point integration scheme. In this work, we propose a linearly consistent one…

Numerical Analysis · Mathematics 2019-04-04 Sundararajan Natarajan , Amrita Francis , Elena Atroshchenko , Stephane PA Bordas

We propose fully explicit projective integration and telescopic projective integration schemes for the multispecies Boltzmann and Bhatnagar-Gross-Krook (BGK) equations. The methods employ a sequence of small forward-Euler steps,…

Numerical Analysis · Mathematics 2022-03-16 Rafael Bailo , Thomas Rey

The linearized collision operator of the Boltzmann equation can in a natural way be written as a sum of a positive multiplication operator, the collision frequency, and an integral operator. Compactness of the integral operator for…

Analysis of PDEs · Mathematics 2023-01-19 Niclas Bernhoff

A volumetric lattice Boltzmann (LB) method is developed for the particle-resolved direct numerical simulation of thermal particulate flows with conjugate heat transfer. This method is devised as a single-domain approach by applying the…

Computational Physics · Physics 2024-11-01 Xiaojie Zhang , Donglei Wang , Qing Li , Rongzong Huang

Cooperative relay systems have become an active area of research during recent years since they help cellular networks to enhance data rate and coverage. In this paper we develop a method to jointly optimize precoding matrices for…

Information Theory · Computer Science 2013-08-09 Ehsan Zandi , Guido Dartmann , Gerd Ascheid , Rudolf Mathar

We study diffusion and mixing in different linear fluid dynamics models, mainly related to incompressible flows. In this setting, mixing is a purely advective effect which causes a transfer of energy to high frequencies. When diffusion is…

Analysis of PDEs · Mathematics 2018-06-11 Michele Coti Zelati , Matias G. Delgadino , Tarek M. Elgindi

In this study, a new subspace-constrained diagonal loading (SSC-DL) method is presented for robust beamforming against the issue of a mismatched direction of arrival (DoA), based on an extension to the well known diagonal loading (DL)…

Optimization and Control · Mathematics 2016-09-30 Yueh-Ting Tsai , Borching Su , Yu Tsao , Syu-Siang Wang

We present recent evolutions of the detailed opacity code SCO-RCG which combines statistical modelings of levels and lines with fine-structure calculations. The code now includes the Partially-Resolved-Transition-Array model, which allows…

Solar and Stellar Astrophysics · Physics 2021-03-10 Jean-Christophe Pain , Franck Gilleron , Thomas Blenski

Wideband communication receivers often deal with the problems of detecting weak signals from distant sources received together with strong nearby interferers. When the techniques of random modulation are used in communication system…

Information Theory · Computer Science 2018-11-15 Dian Mo , Marco F. Duarte