绕弹性水翼空化流动及其流激振动特性研究

Investigations into cavitating flows and flow-induced vibration characteristics around flexible hydrofoil

该文采用基于径向基函数的流固耦合方法,对不同空化数下绕刚性水翼/弹性水翼的空泡形态及其流激振动特性进行了数值模拟。结果表明,绕弹性水翼空泡形态具有三个典型特征:(1)靠近翼尖前缘的附着空泡形态为三角形;(2)翼尖出现梢涡空化,梢涡空化随着空化数的降低而逐渐明显;(3)回射流作用下水翼存在云状空泡的周期性脱落。对不同空化数下弹性水翼的振动特性进行分析发现,随着空化数的下降,水翼振动的平均振幅及振幅波动值先增大再减小,平均振幅和振幅波动由大到小依次是:云空化>超空化>片空化。

In this paper,the fluid-structure coupling strategy based on the radial basis function(RBF) is used to numerically simulate the cavitating flows and the flow-induced vibration characteristics around the rigid/flexible hydrofoil at different cavitation numbers.The results show that there are three typical features of the cavitating flows around the flexible hydrofoil,i.e.,(a) The attached cavity near the leading edge of the hydrof oil tip is triangular,(b) Tip vortex cavitation appears on the hydrofoil tip,and the tip vortex cavitation becomes gradually obviou s with the decrease of cavitation number,and(c) The cloud cavities periodically shed off due to the re-entrant jet.Based on analyses of the vibration characteristics of the flexible hydrofoil under different cavitation numbers,as the cavitation number de creases,both the average amplitude and the amplitude fluctuation of the hydrofoil vibrations firstly increase and then decrease,which are in descending order as cloud cavitation > supercavitation > sheet cavitation.