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 omega 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 hectors; the omega equation can be integrated down to the wall without damping functions. The SST model is a proper two-equation model that performs wall 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 Re-tau=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.