Effects of plane strain on inhomogeneous turbulence

The influence of the mean plane strain on the turbulence transportation is investigated by large eddy simulation (LES) in the shearless turbulence mix ing layer. It is found that the mean strains enhance the turbulent fluctuat ions in the mixing region. Compression in the inhomogeneous direction can g reatly increase the transport of turbulent kinetic energy by triple correla tion terms, while stretching in the inhomogeneous direction decreases the t urbulence transportation. The gradient diffusion models for turbulent trans portation are evaluated and it is found that the intermittency consideratio n can improve the prediction ability of the gradient-type models for the tr iple correlation terms.