An HLLC-type approximate Riemann solver
for ideal magnetohydrodynamics.
Katharine F. Gurski
NIST/MCSD/MMG
Tuesday, November 13, 2001 13:00-14:00,
Room 145, NIST North (820)
Gaithersburg
Tuesday, November 13, 2001 11:00-12:00,
Room 4511
Boulder
Abstract:
In the numerical simulation of magnetohydrodynamic (MHD) problems,
there is a necessary balance between capturing the key features of
the flow, limiting computational expense, and robustness of the
numerical method. This talk will present a new method based on
the HLLC (Harten-Lax-van Leer-contact wave) approximate nonlinear
Riemann solver for gas dynamics for the ideal MHD equations written
in conservation form. This approximation method is intended to be
less diffusive for all problems containing contact waves than
the original HLL (Harten-Lax-van Leer) solver. Compared to exact
nonlinear solvers and Roe's solver, this new solver is computationally
inexpensive. In addition, the method will exactly resolve isolated
shocks and contacts. The method also is guaranteed to preserve
positive density and pressure although in a few cases positivity may
require changing the wavespeeds of the Riemann fan for the underlying
HLL method. Beginning with a review of Riemann problems and the
necessary physical equations, this talk will concentrate more on the
mathematical development of the method than simulation results.
Contact: A. J. KearsleyNote: Visitors from outside NIST must contact
Robin Bickel; (301) 975-3668;
at least 24 hours in advance.
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