ON THE ELIMINATION OF WALL-TOPOGRAPHY PARAMETERS FROM 2-MOMENT CLOSURE

Current generation second-moment closures employ wall proximity/orientation parameters to ensure that the velocity fluctuations normal to the wall die out as the wall is approached faster than fluctuations parallel to the wall. The use of such devices renders the models unsuitable for application to surfaces of even moderately complex shape. It is argued that, for the case of flow parallel to the wall, no such parameters are needed if one adopts a model of the pressure-strain process that rigorously satisfies the two-component limit. The assertion is supported by computations of flow in square and rectangular ducts as well as for the low-Reynolds-number plane channel flow.