绕弹性水翼非定常空化流动模态分析

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.