Temperature jump and slip velocity calculations from an anisotropic scattering kernel

This article deals with the problem of temperature jump and slip velocity at the wall in gas/surface interaction. A consistent modelling of an impermeable surface involving an anisotropic scattering kernel developed in previous works is used to establish boundary conditions in unstructured molecule gas flows. Thus a temperature jump relation is derived in which the gas viscous effects at the wall and the mean velocity gradients appear. Likewise, a slip velocity relation is obtained in which both the slip coeffcient and the thermal creep coeffcient depend on the wall-to-gas temperature ratio. Moreover, both the temperature jump and the slip velocity relations involve not only one accommodation coeffcient as in usual expressions, but also the gas/surface information through the various (notably normal and tangential) accommodation coeffcients of the momentum components.