绕弹性水翼非定常空化流动模态分析  

Modal analysis of unsteady cavitation flow around flexible hydrofoil

作　　者：刘韵晴 郭一梦 吴钦[1] 黄彪[1] 王国玉[1] LIU Yun-qing;GUO Yi-meng;WU Qin;HUANG Biao;WANG Guo-yu(School of Mechanical Engineering,Beijing Institute of Technology,Beijing 100000,Beijing,China)

机构地区：[1]北京理工大学机械与车辆学院,北京100000

出　　处：《水动力学研究与进展（A辑）》2021年第1期35-42,共8页Chinese Journal of Hydrodynamics

基　　金：国家自然科学基金(51839001,51909002和91752105);北京市自然科学基金(3204056)。

摘　　要：采用实验与数值模拟相结合的方法对弹性水翼在云状空化条件下的非定常流动特性和结构振动特性进行分析,采用高速摄像系统和激光多普勒测振系统分别获取水翼空化形态和结构振动特性。数值模拟采用考虑附加水动力效应的混合耦合算法。结果表明:空泡的非定常发展引起结构振动,回射流是导致云状空化断裂和脱落的主要因素。弹性水翼的振动主频与大尺度云状空泡脱落频率一致,其他频率与旋涡脱落频率和水翼的前三阶湿模态频率有关。采用POD方法获取流场主要含能结构,结果表明大尺度云状空化结构占据流场大部分能量。采用DMD方法精确捕捉到了流场的动力学模态特征及其对应频率,进一步验证了空化流激振动与旋涡脱落的关系。The objective of this paper is to study unsteady cloud cavitation flow and vibration characteristics around a flexible hydrofoil by experimental and numerical methods. The high-speed camera is applied to observe the cavitating flow structures and the Laser Doppler Vibrometer is employed to characterize the vibration. The hybrid coupled fluid structure algorithm is adopted to simulate the cloud cavitation dynamics in fluid-structure interaction. The development of cavitation results to the vibration and the re-entrant jet is the main factor for the cavity shedding. The frequency spectrum of vibration shows that the dominant frequency is corresponding to the cloud cavity shedding frequency, others are in accordance with the vortex shedding frequency and the first three wet natural frequency. The results of the Proper Orthogonal Decomposition(POD)applied to extract higher energy modes show that the cloud cavity occupies the largest energy of the flow field. The Dynamic Mode Decomposition(DMD) employed to extract the dominant coherent structures and corresponding frequency reveals the interaction between the vortex shedding and cavitating flow-induced vibration.

关 键 词：云状空化 弹性水翼 旋涡脱落 POD DMD 

分 类 号：O359.1[理学—流体力学]