Second-order slip effects in Poiseuille flow

Plane Poiseuille flow of a rarefied gas was studied in the presence of both a pressure and a temperature gradient under near continuum conditions. Calculations are performed for general gas–gas and gas–surface interactions of the molecules. The second-order slip and the phenomenological coefficients of the symmetric Onsager matrix were explicitly calculated by variational techniques. The slip velocity and the contributions of the Knudsen layer to mass and heat flows are described by a second symmetric matrix.