大涡旋的分类和模式理论的封闭

The Separation of Large Vortexes and the Closed Equations of Turbulence Model

本文依据前文大小涡旋分开考虑的湍流模式,对局部产生的湍流大涡旋引进了新的几率分布,由此引入了一种新的平均过程和平均值.通过这种平均,我们就可以把局部产生的湍流大涡旋和外来的湍流大涡旋进行严格的区分.然后,再引进适当的辅助条件和根据外来干扰的实际情况确定了外来大涡旋的耗散尺度l_N,使得湍流脉动二阶矩的方程组封闭,同时对前文中的一些扩散系数进行了适当的修改.最后,得到了一个封闭的、能够数值求解的方程组.

This paper presents a new kind of average for the locally-generated large vortexes so that the physical quantities of the locally-generated large vortexes and the external large vortexes can be rigorously separated from the equations for the large vortexes proposed in a previous paper[1]. To the equations for the two kinds of large vortexes, some auxiliary relations are introduced, and the value of the length-scale ln of energy dissipation of the external large vortexes may be determined according to the actual circumstances of the disturbance of external sources. Thus, the resulting equations of the second moments of turbulent velocity fluctuations for-the two kinds of large vortexes can be made closed. Meanwhile, the corresponding coefficients of diffusion in the previous paper[1] are improved. Finally, a closed set of numerically-solvable equations of turbulence model are obtained.