Expansion of a gas cloud by the discrete velocity method
Abstract
A discrete velocity model is presented to reduce the Boltzmann equation into a set of equations which are used to solve the unsteady expansion of a rarefied (Kn ranging from 0.1 to infinity) gas cloud bounded by a vacuum. Good agreement is observed among results derived by the present method and those of the free molecular flow method. The discrete velocity method is to divide the moving directions of the molecules into finite (here, two) groups, then a discrete velocity model is formed based on this division. In this way the effect of molecular collisions is taken into account.
 Publication:

AIAA Journal
 Pub Date:
 December 1983
 DOI:
 10.2514/3.60161
 Bibcode:
 1983AIAAJ..21.1618Y
 Keywords:

 Flow Velocity;
 Free Molecular Flow;
 Gas Expansion;
 Rarefied Gas Dynamics;
 Boltzmann Transport Equation;
 Density Distribution;
 Discrete Functions;
 Fluid Mechanics and Heat Transfer