Modelling of turbulent scalar transport in homogeneous turbulence

A transport model for the turbulent heat flux is proposed in consideration with the effect of the mean temperature gradient. A rapid term to express the interaction between the mean temperature and velocity gradients is introduced. The linearity in the exact turbulent heat flux equation is retained in the modelled one, too. The effects of Prandtl number and the turbulent Reynolds number are also taken into account. The comparison is made with existing DNS and experimental data of homogeneous turbulence with and without the mean shear rate and the stable stratification. It indicates that the proposed model agrees well with the DNS and experimental data tested.