A consistent BGK-type model for gas mixtures

Abstract

In this paper we introduce a collision operator for a mixture of gases which satisfies several fundamental properties. Different BGK type collision operators for gas mixtures have been introduced earlier but none of them could satisfy all the basic physical properties: positivity, correct exchange coefficients, entropy inequality, indifferentiability principle. We show that all those properties are verified for our model, and we derive its Chapman-Enskog expansion. In this paper we introduce a collision operator for a mixture of gases which satisfies several fundamental properties. Different BGK type collision operators for gas mixtures have been introduced earlier but none of them could satisfy all the basic physical properties: positivity, correct exchange coefficients, entropy inequality, indifferentiabi- lity principle. We show that all those properties are verified for our model, and we derive its Chapman-Enskog expansion.