Elliptic blending model: A new near-wall Reynolds-stress turbulence closure

A new approach to modeling the effects of a solid wall in one-point second-moment (Reynolds-stress) turbulence closures is presented. The model is based on the relaxation of an inhomogeneous (near-wall) formulation of the pressure-strain tensor towards the chosen conventional homogeneous (far-from-a-wall) form using the blending function alpha, for which an elliptic equation is solved. The approach preserves the main features of Durbin's Reynolds-stress model, but instead of six elliptic equations (for each stress component), it involves only one, scalar elliptic equation. The model, called the elliptic blending model, offers significant simplification, while still complying with the basic physical rationale for the elliptic relaxation concept. In addition to model validation against direct numerical simulation in a plane channel for Re-tau=590, the model was applied in the computation of the channel flow at a real-life Reynolds number of 10(6), showing a good prediction of the logarithmic profile of the mean velocity. (C) 2002 American Institute of Physics.