Compound waves in a thermohydrodynamic lattice BGK scheme using non-perturbative equilibria

Department of Applied Mathematics and Theoretical Physics, University of Cambridge Silver Street, Cambridge CB3 9EW, UK

Corresponding author: pdellar@na-net.ornl.gov

Received: 4 October 2001
Accepted: 3 December 2001

Abstract

A previously proposed thermohydrodynamic lattice BGK scheme using non-perturbative, or non-polynomial, equilibria is found to simulate continuum equations that differ from the Euler equations of gas dynamics at leading order. Shock tube simulations with this BGK scheme coincide with solutions obtained by solving these different continuum equations with conventional methods. Both sets of solutions contain unphysical compound waves, shocks attached to rarefactions, where the Euler equations contain contact discontinuities.