绕弹性水翼非定常空化流激振动特性研究

INVESTIGATION OF FLOW-INDUCED VIBRATION CHARACTERISTICS OF FLEXIBLE HYDROFOIL IN UNSTEADY CAVITATION

该文通过实验和数值计算相结合的方法,对弹性水翼非定常空化流激振动特性进行了研究。实验中,采用高速摄像机获取云状空化不同发展阶段的流动发展规律,应用激光测振仪测量弹性水翼的流激振动特性,通过同步测量技术获取水翼振动特性数据并结合空穴形态图对其进行分析,同时在实验结果基础上加入数值计算部分对流激振动特性进行进一步的说明。研究结果表明:云状空穴的发展为一个准周期过程,包括附着型空穴的生长、空穴的脉动以及空穴的脱落三个阶段;弹性水翼的振动主要受空穴发展过程的影响,因此流激振动特性呈现出周期性的变化过程,且弹性水翼振动主导频率为空穴脱落频率;在不同的空穴发展阶段,表现出不同流激振动特性,并且在空穴脉动和空泡脱落阶段水翼振动较为剧烈。

By combining the experimental studies carried out in a closed-loop cavitation tunnel and the numerical investigation of flow-induced vibration, the flow-induced vibration characteristics of a flexible hydrofoil in unsteady cavitation are investigated. A high-speed video camera is used to visualize the unsteady cavitating flow patterns, and a laser doppler is used to measure the flow-induced vibration characteristics of the flexible hydrofoil. A multi-field synchronous measuring system is used to measure the cavity shape and hydrofoil vibration. Based on the results of the experiment, further numerical study is performed. The results show that：the process of the flow-induced vibration characteristics is a quasi-periodic variation, and one cycle can be divided into three stages which are attached cavity development, cavity fluctuation and cavity shedding. The flow-induced vibration is mainly influenced by the development of the cavitation, and the main frequency is corresponding to the cavity shedding frequency. During the different process of the cavitation development, it shows the different variation characteristics, and the variation is fiercer during the stages of cavity fluctuation and cavity shedding.