Capturing the Knudsen layer in continuum-fluid models of non-equilibrium gas flows

Lockerby, Duncan A. and Reese, Jason M. and Gallis, Michael A. (2005) Capturing the Knudsen layer in continuum-fluid models of non-equilibrium gas flows. AIAA Journal, 43 (6). pp. 1391-1393. ISSN 0001-1452

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Abstract

In hypersonic aerodynamics and microflow device design, the momentum and energy fluxes to solid surfaces are often of critical importance. However, these depend on the characteristics of the Knudsen layer - the region of local non-equilibrium existing up to one or two molecular mean free paths from the wall in any gas flow near a surface. While the Knudsen layer has been investigated extensively using kinetic theory, the ability to capture it within a continuum-fluid formulation (in conjunction with slip boundary conditions) suitable for current computational fluid dynamics toolboxes would offer distinct and practical computational advantages.