A LOW-REYNOLDS-NUMBER, 4-EQUATION HEAT-TRANSFER MODEL FOR TURBULENT SEPARATED AND REATTACHING FLOWS

An algebraic heat flux model is applied to predict turbulent heat tran sfer in separated and reattaching flows. Based on the prior low-Reynol ds-number k-epsilon model of Park and Sung (1995), an improved version of the nonequilibrium heat transfer model is developed. The model per formance is examined by solving the equations of the temperature varia nce k(theta) and its dissipation rate epsilon(theta), together with th e equations of k and epsilon. In the present model, the near-wall limi ting behaviour close to the wall and the nonequilibrium effect away fr om the wall are incorporated. A tensor eddy-diffusivity is obtained to implement the orientation of mean temperature gradient in separated a nd reattaching flows. The validation of the model is applied to the tu rbulent flow over a backward facing step. The predictions of the prese nt model are cross-checked with the existing measurements and direct n umerical simulation (DNS) data. The model performance is shown to be g enerally satisfactory. (C) 1997 by Elsevier Science Inc.