VALIDATION OF A NEW VELOCITY-SLIP MODEL FOR SEPARATED GAS MICROFLOWS

A recently developed high-order velocity-slip boundary condition is validated for gas microflows, by comparing predictions of the new model against the first-order slip condition and the direct-simulation Monte Carlo (DSMC) results. Numerical solutions of gas flow through microchannels and backward-facing step geometry are presented. The backward-facing step geometry is a suitable testbed for studying gas microflows subject to strong adverse pressure gradients and separation. The new slip boundary condition, based on obtaining the slip information one mean free path away from the surface, results in good agreement with the DSMC for both attached and separated flows.

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