Title: Thermal creep flow of rarefied gases in rectangular enclosures: a comparison between the Navier-Stokes and Burnett models

Authors: M. Orhan, A. Ecder, A. Tezel

Addresses: Department of Mechanical Engineering, Bogazici University, Istanbul 34342, Turkey. ' Department of Mechanical Engineering, Bogazici University, Istanbul 34342, Turkey. ' Department of Mechanical Engineering, Bogazici University, Istanbul 34342, Turkey

Abstract: Thermal creep flow of rarefied gases in enclosures has been investigated numerically by employing Navier-Stokes (NS) and augmented Burnett equations as mathematical models. An explicit multistage time stepping scheme has been exploited to solve cell centred finite volume representations of the governing equations. We have investigated the momentum diffusion mechanism by comparing computed stress components of both models at each order and we conclude that the flow can be assumed, like a purely shear driven flow, diffusion dominated motion because of the linearly varying first order shear. The analyses show that the creep velocity could not be ignored in the continuum limit. We furthermore observed that as Kn number increases, the maximum creep velocity resulting from the Burnett model decreases in contrast to NS equations.

Keywords: thermal transpiration flow; Burnett equations; stress; Navier-Stokes equations; creep flow; rarefied gases; rectangular enclosures; momentum diffusion; creep velocity; CFD; computational fluid dynamics.

DOI: 10.1504/PCFD.2007.014962

Progress in Computational Fluid Dynamics, An International Journal, 2007 Vol.7 No.7, pp.404 - 413

Published online: 28 Aug 2007 *

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