Abstract
CFD calculations of turbulent flow near smooth walls generally employ one of two broad strategies to resolve the very influential, complex, but thin near-wall viscosity-affected sub-layer. One approach uses a fine numerical mesh and a turbulence model incorporating viscous influences; the other employs "wall functions"—formulae that attempt to account for the overall resistance of the sublayer to momentum and heat transport. The latter requires only a fraction of the computational effort of the former and is thus strongly favoured for industrial calculations. However, the wall-function performance is often poor, partly because of inappropriate implementations and partly because the schemes themselves have inherent limitations.
The present paper reviews the evolution of wall-function strategies. Attention is then given to two new schemes developed by the authors, one based on an analytical treatment and the other on a numerical resolution of the near-wall sub-layer. Several applications are shown of mixed and forced convection.
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Communicated by F Hamba