计算风工程中k-ε模型的一类边界条件

A set of turbulence boundary condition of k-ε model for CWE

给定适当的湍流来流边界条件是计算风工程中一个重要的问题。然而通常情况下 ,由于问题的复杂性 ,很难给定一个既满足边界层自保持要求又与试验相符的边界条件。本文首先从模型方程本身出发 ,推导出一类近似满足κ ε模型自保持边界条件要求的湍动能表达式。此表达式与有关文献建议的湍流边界条件比较 ,可以考虑湍动能随高度的变化 ,因而更符合实测规律 ;然后基于风洞试验数据 ,定义了一组k ε模型中的模型常数 ;最后通过模拟风洞试验的算例 ,验证并分析了此类湍动能边界条件配合试验常数 ,在标准k

Setting appropriate turbulence boundary condition is an important problem in numerical simulation for CWE (computational wind engineering). But in general, it is difficult to give inflow boundary conditions which could produce an equilibrium boundary layer as well as consist with the experimental data. In this paper, a type of inflow TKE (turbulence kinetic energy) expression is presented based on the κ-ε model equations firstly. Compared with the turbulence inflow boundary conditions suggested by Richards and Hoxey^(), this inflow TKE boundary condition could consider the variation of TKE with the height above the ground. Then a set of constants in standard κ-ε model are defined according to the wind tunnel test data. The applicability of producing the self-sustaining atmosphere boundary layer using this inflow turbulence boundary condition is verified numerically in standard κ-ε model combining with wind tunnel test constants.