2024-11-22 Friday Sign in CN

Activities
High order asymptotic preserving finite difference schemes with constrained transport for MHD equations in all sonic Mach numbers
Home - Activities
Reporter:
Tao Xiong, Professor, University of Science and Technology of China
Inviter:
Shipeng Mao, Professor
Subject:
High order asymptotic preserving finite difference schemes with constrained transport for MHD equations in all sonic Mach numbers
Time and place:
10:00-11:00 April 30(Tuesday) , S723
Abstract:

In this work, a high-order semi-implicit (SI) asymptotic preserving (AP) and divergence free finite difference weighted essentially nonoscillatory (WENO) scheme is proposed for magnetohydrodynamic (MHD) equations. We consider the sonic Mach number ε ranging from 0 to O(1). High-order accuracy in time is obtained by SI implicit-explicit Runge-Kutta (IMEX-RK) time discretization. High-order accuracy in space is achieved by finite difference WENO schemes with characteristic-wise reconstructions. A constrained transport method is applied to maintain a discrete divergence-free condition. We formally prove that the scheme is AP. Asymptotic accuracy (AA) in the incompressible MHD limit is obtained if the implicit part of the SI IMEX-RK scheme is stiffly accurate. Numerical experiments are provided to validate the AP, AA, and divergence-free properties of our proposed approach. Besides, the scheme can well capture discontinuities such as shocks in an essentially non-oscillatory fashion in the compressible regime, while it is also a good incompressible solver with uniform large-time step conditions in the low sonic Mach limit.