NONLINEAR KINETIC EFFECTS IN THE COUETTE PROBLEM FOR A RAREFIED GAS IN THE TRANSITION REGION

Abstract

We consider the Couette problem of a gas flow and heat transfer between two parallel infinite plates located at a distance h from each other, with one plate resting and the other moving in its own plane at a constant velocity W. The temperatures of the plates are T0 and T1, respectively. The normal and tangential components of the stress tensor and the heat flux to the surface of the plates are calculated. The results obtained by the direct simulation Monte-Carlo method are compared with the analytical ones using the self-similar interpolation method. The results show that in the transition region between the free-molecular flow and continuous flow, the stress tensor has two components: the tangent one and the normal one, which is absent both in the free-molecular case and in the case of a continuous flow. Moreover, the normal and tangential components are essentially non-monotonic in the range of Knudsen numbers. The heat flux also has a non-monotonic behavior and changes its sign with a change in the Knudsen number (gas rarefaction factor Kn).