IMPROVED SHOCK-CAPTURING METHODS FOR MULTICOMPONENT AND REACTING FLOWS

Existing shock-capturing schemes have difficulties with multispecies c omputations, creating nonphysical glitches at species interfaces. We a ttribute these glitches to inconsistencies in the equation of state in cells containing several species. Our remedy is to define mixtures wi thin a grid cell as a collection of species which can possess distinct temperatures. This formulation requires solving an additional set of species energy equations. Computational results show that the glitches have been eliminated. For chemically reacting flow simulations, exist ing splitting methods often generate nonphysical waves at stiff reacti on fronts. We show that this numerical phenomenon is due to the mixtur e model that overestimates the reaction temperature. This is avoided b y introducing an enforcement on the reaction temperature that depends on the temperatures of each species. We demonstrate that the method co mputes detonation waves with time steps and grid sizes much larger tha n would be allowed to resolve reaction zones. (C) 1996 Academic Press, Inc.