VOLUME VISCOSITY OF DILUTE POLYATOMIC-GAS MIXTURES

We present two linear systems with which to evaluate the rotational vo lume viscosity of dilute polyatomic gas mixtures. These systems are gi ven in their naturally symmetric constrained singular form. In the tra nslational-and-rotational-energy approach, the linear system of Monchi ck, Yun, and Mason can be recovered if one misprint is corrected in th eir expressions. In the rotational-energy approach, a new linear syste m is obtained, thereby yielding a new approximation for the volume vis cosity. We also discuss an extension of the present theory to the vibr ational volume viscosity. Using iterative methods, we then derive expl icit expressions for the rotational volume viscosity that can be imple mented at a low computational cost in practical applications. The accu racy of these approximate expressions is illustrated with numerical ex amples. These expressions are relevant to several compressible flow ap plications, such as flames, chemical reactors, and high-speed entry in to planetary atmospheres.