二维水翼非定常空化流动动力特性的频谱分析

摘要

Based on the RANS equations,RNG k-ε turbulent models and homogeneous multi-phase cavitation models are used to simulate the cavitation flow around the two-dimensional hydrofoil.In the case of the constant inlet velocity and cavitation number,the cavitation profiles changing with the at-tack angle are researched,and the spectrum analysis of the hydrofoil is carried out by the FFT me-thod.The results show that the cavitation profiles are determined by the cavitation number and the angle of attack.If the cavitation number is constant,the cavitation will be more intensive as the angle of attack increases.In the case of foliated cavitation,the lift signal is a low-frequency signal,which will decrease a little with an increase in the attack angle.In the case of clouds cavitation,the lift sig-nal is a medium-high-frequency signal,which will also decrease a little with an increase in the attack angle.From the foliated cavitation to the clouds cavitation,there is a transition in the conversion process,in which the frequency of the lift signal has various characteristics in every channel.%以雷诺平均模拟方程（RANS）为核心，采用 RNG k-ε湍流模型与均相流空化模型，对二维水翼附近空化流场进行数值计算。在固定来流速度和空化数条件下，研究了空化形态随着水翼攻角的改变而变化的情况，并采用傅立叶变换（FFT）对水翼升力周期性信号进行了频谱分析。结果表明：水翼的空化形态是由空化数和攻角共同决定的，当空化数不变时，随着攻角的增大，空化程度更加趋于剧烈；在片状空化阶段，升力信号频率为低频信号，并随着攻角增大频率略有降低；在云状空化阶段，升力信号频率为中高频信号，随着攻角增大频率也略有降低；空化形态由片状空化阶段向云状空化阶段转化，在转化过程中存在一个过渡阶段，其升力信号频率在各个频段均具有一定的特征。