水平风作用下雨滴水平速度的数值仿真

摘要

为了研究雨滴在水平风作用下的水平移动情况,在分析水平风作用下雨滴受力情况的基础上,通过对曳力系数与雷诺数对应关系的研究,采用数值仿真的方法分别对海平面大气条件和不同大气条件下雨滴水平运动速度进行仿真.结果表明:当有水平风作用时,雨滴的水平运动速度不等于风的速度,而是随雨滴直径和水平风速的变化而变化；在水平风作用下,雨滴的水平移动速度可以在较短的时间内(一般小于15 s)达到一个稳定的值；在水平风速相同的情况下,气压越高、温度越低,雨滴达到平衡时的水平移动末速度相对越大,反之则越小.这些结论对基于图像采集原理的光学降水自动观测仪器进行雨滴图像拼合有重要的应用价值.%To investigate the raindrop horizontal velocity in wind,the raindrop horizontal moving velocity under different atmospheric conditions was simulated based on the stress of raindrop in wind and the relationship of drag coefficient and Reynolds numbers in this paper.Simulation results indicated that the raindrop horizontal velocity is unequal to the velocity of wind,and the raindrop terminal horizontal velocity varies with the raindrop diameter and the velocity of wind ; the raindrop can reach a steady horizontal velocity in a short period of time(commonly less than 15 s) affected by the wind; under the same wind condition,the higher the altitude is and the lower the air pressure and environment temperature are,the higher terminal horizontal velocity of raindrop is,and vice versa.These conclusions are of great practical importance to raindrop image mosaic for automatic optical precipitation-measuring system based on the principle of image acquisition.