Free-path distribution and Knudsen-layer modeling for gaseous flows in the transition regime.

In this paper, we use molecular dynamics (MD) simulations to study the mean free path distribution of nonequilibrium gases in micronanochannel and to model the Knudsen (Kn) layer effect. It is found that the mean free path is significantly reduced near the wall and rather insensitive to flow types (Poiseuille or Couette). The Cercignani relation between the mean free path and the viscosity is adopted to capture the velocity behavior of the special zone in the framework of the extended Navier-Stokes (NS) equations.

Tensorial slip theory for gas flows and comparison with molecular dynamics simulations using an anisotropic gas-wall collision mechanism.

In this paper we examine the anisotropic slip theory for gas flows based on tangential accommodation coefficients and compare it with molecular dynamics (MD) results. A special gas-wall boundary condition is employed within MD simulations to mimic the anisotropic gas-wall collision mechanism. Results from MD simulations with different surface orientations show good agreement with the slip quantification proposed in this work.

Effects of surface morphology and anisotropy on the tangential-momentum accommodation coefficient between Pt(100) and Ar.

In this paper, we study the influence of platinum (100) surface morphology on the tangential-momentum accommodation coefficient with argon using a molecular dynamics method. The coefficient is computed directly by beaming Ar atoms onto the surfaces and measuring the relative momentum changes. The wall is maintained at a constant temperature and its interaction with the gas atoms is governed by the Kulginov potential.