Crank-Nicolson BGK Integrator for Multi-Scale Particle-Based Kinetic Simulations

Fuente: arXiv
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Auteurs principaux: Pfeiffer, Marcel, Garmirian, Félix, Ott, Tobias
Format: Preprint
Publié: 2024
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author Pfeiffer, Marcel
Garmirian, Félix
Ott, Tobias
author_facet Pfeiffer, Marcel
Garmirian, Félix
Ott, Tobias
contents Solving the Bhatnagar-Gross-Krook (BGK) equation with a stochastic particle approach enables efficient and flexible simulations of flows in the transition regime, between continuum and free molecular flow. However, the usual first-order operator splitting between particle movement and relaxation imposes restrictions on the time step, causing the computational cost to increase with the gas density. The Crank-Nicolson stochastic particle BGK (CN-SPBGK) method is introduced here as an advanced particle-based kinetic solver designed for multi-scale gas flow simulations. This method integrates the BGK equation with second-order accuracy across all Knudsen number regimes without requiring additional parameters, while asymptotically preserving the Navier-Stokes flux in the continuum regime. Comparisons with pre-existing particle BGK methods are conducted on several test cases, with CN-SPBGK demonstrating more consistent convergence and accuracy.
format Preprint
id arxiv_https___arxiv_org_abs_2411_19076
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Crank-Nicolson BGK Integrator for Multi-Scale Particle-Based Kinetic Simulations
Pfeiffer, Marcel
Garmirian, Félix
Ott, Tobias
Fluid Dynamics
Computational Physics
Solving the Bhatnagar-Gross-Krook (BGK) equation with a stochastic particle approach enables efficient and flexible simulations of flows in the transition regime, between continuum and free molecular flow. However, the usual first-order operator splitting between particle movement and relaxation imposes restrictions on the time step, causing the computational cost to increase with the gas density. The Crank-Nicolson stochastic particle BGK (CN-SPBGK) method is introduced here as an advanced particle-based kinetic solver designed for multi-scale gas flow simulations. This method integrates the BGK equation with second-order accuracy across all Knudsen number regimes without requiring additional parameters, while asymptotically preserving the Navier-Stokes flux in the continuum regime. Comparisons with pre-existing particle BGK methods are conducted on several test cases, with CN-SPBGK demonstrating more consistent convergence and accuracy.
title Crank-Nicolson BGK Integrator for Multi-Scale Particle-Based Kinetic Simulations
topic Fluid Dynamics
Computational Physics
url https://arxiv.org/abs/2411.19076