基于LES方法两种接缝足球升阻力计算及飘球的力学分析

建立两种接缝形式足球的几何模型，通过LES方法计算足球模型的升阻力及相应流场情况．计算结果与相关文献对比，分析了计算误差的来源，并提出可行的处理方案．计算得到模型表面的接缝使得边界层分离点前移，分离区增大，从而阻力增大．计算结果同时表明，两种接缝对阻力的影响是相当的，对升力影响却不可忽视．计算得到升力的变化情况，并从涡脱落角度分析其特征．在此基础上，对“超自然现象”的飘球的力学机理进行了探讨．

A Study of Aerodynamics of Soccer Ball with Two Type Seams Based on LES Method and Mechanical Analysis of Knuckling Ball

Two computational soccer models with different seams were set up, then by the means of LES method the flow field, lift and drag coefficient were obtained. Compared with the results reported in related articles, the difference between these results and the computational ones were analyzed. And a reasonable solution was came up with in the paper. These results indicate that the seams on the surface of the model advance the location of boundary layer separation, then the separation region was enlarged, and the drag increased. The influence of two type seams on the drag is not obvious but may not be ignored on the lift. By analyzing the vortex shedding from the surface of the model, it was tried to understand the random variation of the lift. Based upon these, an explanation of the mechanics behind the so-called ‘supernatural’ knuckling ball was attempted.