PROBABILITY DENSITY-FUNCTION AND REYNOLDS-STRESS MODELING OF NEAR-WALL TURBULENT FLOWS

Probability density function (pdf) methods are extended to include mod eling of wall-bounded turbulent flows. A pdf near-wall model is develo ped in which the generalized Langevin model is combined with an exact model for viscous transport. Then the method of elliptic relaxation is used in incorporate the wall effects without the use of wall function s or damping functions. Information about the proximity of the wall is provided only in the boundary conditions so that the model can be imp lemented without ad hoc assumptions about the geometry of the flow. A Reynolds-stress closure is derived from this pdf model, and its predic tions are compared with DNS and experimental results for fully develop ed turbulent channel flow. (C) 1997 American Institute of Physics.