Velocity Slip and Temperature Jump for Gas Flows Past Anisotropic Surfaces: Analytical Derivation and Numerical Simulation

In this paper, we present a development on the theory and simulation method for gas flows inside a micro/nano-channel confined between anisotropic walls. Typical examples of those structures are orthorhombic crystal surfaces, unequally strained crystals, surfaces containing parallel stripes at atomic scale or even randomly rough surfaces whose profile distributions are anisotropic, etc... As a result, the gas-wall collision behavior depends strongly on the direction and cannot be captured by traditional isotropic models, e.g Maxwell or Cercignani-Lampis (CL) [1, 2]. These effects have been shown by our previous work based on MD simulations of beam scattering experiments. In particular, the tangential accommodation coefficient varies with the projection direction of the gas atom onto the solid wall surface [3].