Numerical passage from kinetic to fluid equations
SIAM Journal on Numerical Analysis
Rarefied flow computations using nonlinear model Boltzmann equations
Journal of Computational Physics
Efficient Asymptotic-Preserving (AP) Schemes For Some Multiscale Kinetic Equations
SIAM Journal on Scientific Computing
High order numerical methods for the space non-homogeneous Boltzmann equation
Journal of Computational Physics
Accurate numerical methods for the collisional motion of (heated) granular flows
Journal of Computational Physics
Solving the Boltzmann Equation in N log2 N
SIAM Journal on Scientific Computing
Implicit—Explicit Schemes for BGK Kinetic Equations
Journal of Scientific Computing
Journal of Computational Physics
Microscopically implicit-macroscopically explicit schemes for the BGK equation
Journal of Computational Physics
Exponential Runge-Kutta Methods for Stiff Kinetic Equations
SIAM Journal on Numerical Analysis
Journal of Computational Physics
Exponential Runge-Kutta for the inhomogeneous Boltzmann equations with high order of accuracy
Journal of Computational Physics
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In this paper, we study a time discrete scheme for the initial value problem of the ES-BGK kinetic equation. Numerically solving these equations are challenging due to the nonlinear stiff collision (source) terms induced by small mean free or relaxation time. We study an implicit-explicit (IMEX) time discretization in which the convection is explicit while the relaxation term is implicit to overcome the stiffness. We first show how the implicit relaxation can be solved explicitly, and then prove asymptotically that this time discretization drives the density distribution toward the local Maxwellian when the mean free time goes to zero while the numerical time step is held fixed. This naturally imposes an asymptotic-preserving scheme in the Euler limit. The scheme so designed does not need any nonlinear iterative solver for the implicit relaxation term. Moreover, it can capture the macroscopic fluid dynamic (Euler) limit even if the small scale determined by the Knudsen number is not numerically resolved. We also show that it is consistent to the compressible Navier-Stokes equations if the viscosity and heat conductivity are numerically resolved. Several numerical examples, in both one and two space dimensions, are used to demonstrate the desired behavior of this scheme.