细网格非静力二维高阶闭合模式对山体流场特征的模拟分析

SIMULATIVE ANALYSIS FOR THE CHARACTERISTICS OF RIDGE TURBULENT FLOW FIELD BY USING A TWO-DIMENSION FINE-MESH NON-HYDROSTATIC HIGHER ORDER TURBULENCE CLOSURE MODEL

本文采用二阶矩湍流闭合方案，分别就非静力和准静力两种条件建立ＰＢＬ数值模式，并模拟了二维山脊流场的结构，计算了二维山体对气流平均场和湍流场的影响。计算结果表明，无论是平均场还是湍流场，采用准静力假设都会造成模拟结果的较大偏差，且对平均场的影响比对湍流场的影响更为显著。两种模式计算结果的差别还随地形坡度和背景风增大而增大。

The effects of a 2-D ridge flow field on the mean flow and turbulence structure in the neutral surface layer were numerically investigated by using a non-hydrostatic higher-order turbulence closure model developed in this paper. The influences of the shape of the hill and the surface roughness of ridge on the fluctuation of flow around hill were discussed. The results show that a large discrepance was produced when the hydrostatic assumption was adopted, especially on the mean flow field. When the hill become steeper or background wind speed become larger,this discrepance is more considerable.