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

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