不同大气条件雨滴下落速度的数值仿真

Numerical Simulation of Terminal Velocity of Raindrops Falling under Different Atmospheric Conditions

研究降雨优化预测准确性问题,雨滴的下落末速度是仪器测量降水的重要参数。降水识别仪器根据建立的雨滴下落的理论模型,对降水进行准确预测和识别。为了得到雨滴下落末速度的精确测量,结合曳力系数和雷诺数的对应关系,利用龙格—库塔(Runge-Kutta)法求解,得到了雨滴的下落末速度,并与Gunn&Kinzer雨滴下落末速度实测值作对比。结果表明,数值仿真与预测值吻合较好,结果更为精确。通过仿真了不同大气条件下的雨滴下落末速度,得到了Best经验公式的系数。结果证明,对降水识别模型的建立具有重要的应用价值,为精确识别提供了依据。

Terminal velocity of raindrops is an important parameter of measuring instrument.In order to get accurate simulation of the raindrops＇ terminal velocity and correct measurement error of the apparatus,the article established the theoretical model of falling raindrops,and solved the differential equations during the raindrops fall using the Runge-Kutta method with the corresponding relationship of drag coefficient and Reynolds number,obtained the terminal velocity of raindrops and compared results with the actual measurement of GunnKinzer.The results show that the value of numerical simulation agrees well with them with more accurate.Finally,the simulation of raindrops falling under different atmospheric conditions was presented,and obtained the coefficient of Best empirical formula.The simulation result is more applicability,which has an important application value to the recognition of precipitation.