TWO-EQUATION MODEL FOR HEAT TRANSPORT IN WALL TURBULENT SHEAR FLOWS.

A new proposal for closing the energy equation is presented at the two-equation level of turbulence modeling. The eddy diffusivity concept is used in modeling. However, just as the eddy viscosity is determined from solutions of the k and epsilon equations, so the eddy diffusivity for heat is given as functions of temperature variance t OVER BAR **2 and the dissipation rate of temperature fluctuations epsilon //t, together with k and epsilon . Thus, the proposed model does not require any questionable assumptions for the 'turbulent Prandtl number. ' Modeled forms of the t OVER BAR **2 and epsilon //t equations are developed to account for the physical effects of molecular Prandtl number and near-wall turbulence. The model is tested by application to a flat-plate boundary layer, the thermal entrance region of a pipe, and the turbulent heat transfer in fluids over a wide range of the Prandtl number.