热流数值计算中网格效应的研究

Study on the grid effect in the numerical calculation of heat flux

以高超声速零攻角钝头圆锥为研究对象,选择不同的网格分布,利用直接数值模拟(DNS)方法计算表面热流,以分析网格分布对钝头表面热流计算的影响。研究发现,流向网格雷诺数和法向网格雷诺数均对驻点热流计算具有一定的影响,因此为准确计算表面热流,需要选择合理的网格分布。研究还发现,能够准确求解驻点热流需要达到的最低法向网格雷诺数低于非驻点区表面热流的精度要求,故准确求解出驻点热流是求解表面热流的关键。

In this paper, an analysis is conducted on the blunt cone featuring the hypersonic zero attack angle in different types of grid distribution. By means of direct numerical simulation（DNS）, the surface heat flux is calculated, in order to illustrate the influence of grid distribution exerted on the calculation of heat flux on the blunt surface. The result shows that both streamwise grid Reynolds number and normal grid Reynolds number have exerted certain influence on the calculation of stagnation-point heat transfer. Therefore, in order to accurately calculate the surface heat flux, it is necessary to choose a proper type of grid distribution. It is also found that the minimum normal grid Reynolds number for accurately solving the stagnation-point heat flux is lower than that for the heat flux of non-stagnation surface. Thus, calculating the stagnation-point heat transfer is the key to solving the surface heat flux.