An ultra-sparse approximation of kinetic solutions to spatially homogeneous flows of non-continuum gas

We consider a compact approximation of the kinetic velocity distribution function by a sum of isotropic Gaussian densities in the problem of spatially homogeneous relaxation. Derivatives of the macroscopic parameters of the approximating Gaussians are obtained as solutions to a linear least squares...

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Main Authors: Alexander Alekseenko, Amy Grandilli, Aihua Wood
Format: Article
Language:English
Published: Elsevier 2020-02-01
Series:Results in Applied Mathematics
Online Access:http://www.sciencedirect.com/science/article/pii/S2590037419300858
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author Alexander Alekseenko
Amy Grandilli
Aihua Wood
author_facet Alexander Alekseenko
Amy Grandilli
Aihua Wood
author_sort Alexander Alekseenko
collection DOAJ
description We consider a compact approximation of the kinetic velocity distribution function by a sum of isotropic Gaussian densities in the problem of spatially homogeneous relaxation. Derivatives of the macroscopic parameters of the approximating Gaussians are obtained as solutions to a linear least squares problem derived from the Boltzmann equation with full collision integral. Our model performs well for flows obtained by mixing upstream and downstream conditions of normal shock wave with Mach number 3. The model was applied to explore the process of approaching equilibrium in a spatially homogeneous flow of gas. Convergence of solutions with respect to the model parameters is studied. MSC: 76P05, 76M10, 65M60, Keywords: Boltzmann equation, Sparse approximation, Kinetic solutions, Non-continuum gas
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spelling doaj.art-92167d2b984048e1b0f2c4535c5e36bb2022-12-21T19:18:01ZengElsevierResults in Applied Mathematics2590-03742020-02-015An ultra-sparse approximation of kinetic solutions to spatially homogeneous flows of non-continuum gasAlexander Alekseenko0Amy Grandilli1Aihua Wood2Department of Mathematics, California State University Northridge, Northridge, CA 91330, USA; Corresponding author.Department of Mathematics, California State University Northridge, Northridge, CA 91330, USADepartment of Mathematics & Statistics, Air Force Institute of Technology, WPAFB, OH 45433, USAWe consider a compact approximation of the kinetic velocity distribution function by a sum of isotropic Gaussian densities in the problem of spatially homogeneous relaxation. Derivatives of the macroscopic parameters of the approximating Gaussians are obtained as solutions to a linear least squares problem derived from the Boltzmann equation with full collision integral. Our model performs well for flows obtained by mixing upstream and downstream conditions of normal shock wave with Mach number 3. The model was applied to explore the process of approaching equilibrium in a spatially homogeneous flow of gas. Convergence of solutions with respect to the model parameters is studied. MSC: 76P05, 76M10, 65M60, Keywords: Boltzmann equation, Sparse approximation, Kinetic solutions, Non-continuum gashttp://www.sciencedirect.com/science/article/pii/S2590037419300858
spellingShingle Alexander Alekseenko
Amy Grandilli
Aihua Wood
An ultra-sparse approximation of kinetic solutions to spatially homogeneous flows of non-continuum gas
Results in Applied Mathematics
title An ultra-sparse approximation of kinetic solutions to spatially homogeneous flows of non-continuum gas
title_full An ultra-sparse approximation of kinetic solutions to spatially homogeneous flows of non-continuum gas
title_fullStr An ultra-sparse approximation of kinetic solutions to spatially homogeneous flows of non-continuum gas
title_full_unstemmed An ultra-sparse approximation of kinetic solutions to spatially homogeneous flows of non-continuum gas
title_short An ultra-sparse approximation of kinetic solutions to spatially homogeneous flows of non-continuum gas
title_sort ultra sparse approximation of kinetic solutions to spatially homogeneous flows of non continuum gas
url http://www.sciencedirect.com/science/article/pii/S2590037419300858
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