Аннотация:A new computational model for the return to isotropy is presented. In order to reproduce the significant role of the third invariant IIIb(=bijbjkbki) of the Reynolds stress anisotropy bij[=uiuj/(2k)−(1/3)δij] in the return-to-isotropy process, a nonlinear return-to-isotropy model is formulated by a Taylor series expansion up to fifth power of bij. Then the strong realizability condition for non-negativity of the component energies is utilized to reduce the number of model constants produced. Correction for the low Reynolds number effect is then included by investigating an energy-weighted average time scale of eddies over the three-dimensional energy spectrum. Superiority of the proposed model performance is exemplified by a number of test computations of homogeneous relaxing turbulence in a wide range of turbulence Reynolds number and IIIb.
