摘要
利用商业CFD软件对小空泡数下的自然超空泡形态和减阻效果进行了数值仿真研究,通过对软件自定义函数的研究,将边界条件中的来流速度改写为时间的函数并嵌入到软件中,得到了非定常情况下加速度对自然超空泡形态和减阻效果的影响规律。当加速度为正值时,在空泡数相同的条件下空泡的厚度和长度都要比定常条件下的值偏小,而加速度为负值时则刚好相反。模型的粘性阻力系数与加速度没有直接的联系,它主要与超空泡的形态和模型壁面上的含汽率有关。最后将加速度为-100m/s2时的仿真结果与实验结果进行了比较,误差最大不超过35%。
Natural supercavity shape and its drag reduction at small cavitation number have been numerically simulated with Finite Difference code CFD. User-Defined Functions （UDFs） for the time-dependent free stream velocity was implemented into CFD software. The effects of acceleration on natural supercavity shape and its drag reduction have been obtained. With the same cavitation number, the thickness and length of supercavity are smaller at positive acceleration than those at zero acceleration, and larger than those at negative acceleration. Viscous drag coefficient has no direct relations with acceleration, which is mainly related to supercavity shape and vapor volume fraction in supercavity. The numerical results are compared with the experimental results at acceleration of-100 m/s^2, and the maximal error does not exceed 35%.
出处
《工程力学》
EI
CSCD
北大核心
2007年第1期18-22,共5页
Engineering Mechanics
关键词
超空泡
空泡形态
数值仿真
粘性阻力
空化数
supercavity： cavity shape： numerical simulation： viscosity drag
cavitation number
