Highly rarefied gas around a group of bodies with various temperature distributions. II - Arbitrary temperature variation

An analytical investigation is carried out to obtain a general solution for the collisionless Boltzmann equation for the steady-state behavior of a free molecular gas around bodies at rest. It is assumed that various, arbitrarily varying temperatures are present. A governing velocity equation is established for the gas molecules, along with a Maxwellian boundary condition and an accommodation coefficient to account for diffuse reflection at the boundaries. Thermal creep and thermal stress flows are found to be absent in a closed system. When applied to the situation of two molecular gases in reservoirs joined by a pipe, no flow occurs.