Development of a gradient diffusion type of Heat-Flux model with an introduction of a quadratic reynolds stress tensor

A new explicit algebraic gradient diffusion model for turbulent scalar (heat) flux in forced convection regimes is proposed. This model complies with the linearity and independence principles for passive scalar. For satisfying these, the model coefficients/functions do not include any turbulent scalar variable such as the temperature variance. The model thus does not require solving transport equations for turbulent quantities of the scalar field. The basic role of each model coefficient has been optimized by referring to the discussion with the LES data reported by the authors. The proposed model is applicable to a wide range of passive scalar fields by being coupled wh a nonlinear k-E- A three equation turbulence model for dynamic fields. It has been confirmed that the model is able to capture the components of turbulent heat flux vectors in wall shear flows at least in the range of 0.025 &lE Pr &lE 95. Moreover, it has successfully distinguished the heat flux characteristics near shear- free boundaries.