A New Low Reynolds Stress Transport Model for Heat Transfer and Fluid in Engineering Applications

A new Reynolds stress transport model (RSTM) aimed for engineering applications is proposed with consideration of near-wall turbulence. This model employs the Speziale, Sarkar, and Gatski (SSG) pressure strain term, the $ω$ equation, and the shear stress transport (SST) model for the shear stresses at the near-wall region (say, $y+<30$⁠). The models are selected based on the following merits: The SSG RSTM model performs well in the fully turbulent region and does not need the wall normal vectors; the $ω$ equation can be integrated down to the wall without damping functions. The SST model is a proper two-equation model that performs well for flows with adverse pressure gradient, while most two-equation models can have a good prediction of the shear stresses. A function is selected for the blending of the RSTM and SST. Three cases are presented to show the performance of the present model: (i) fully developed channel flow with $Reτ$=395, (ii) backward-facing step with an expansion ratio of 1.2 and Re=5200 base on the step height, and (iii) circular impingement with the nozzle-to-wall distance H=4D and Re=20,000. It is believed that the new model has good applicability for complex flow fields.