Complex microscale flow simulations using Langmuir slip condition

Abstract

Langmuir slip boundary condition combined with macroscopic governing equations is suggested to simulate microscale gas flows. The concept is numerically implemented and verified, with the focus on analyzing complex gaseous flows involving separation. Compressible backward-facing step flow is compared to other analysis results with the purpose of diatomic gas Langmuir slip condition validation. Numerical analysis is performed for Reynolds number from 10 to 60 for a prediction of separation at a T-shaped micromanifold. The numerical solutions of velocity and shear stress distributions at walls are in good agreement with other numerical results. Nonlinear behavior is clearly present in several parameter studies, including reattachment length at the wall of side branch. It is substantiated from these results that the Langmuir slip condition predicts appropriately the physics in complex microscale gas flows even with separation.