Experiment and numerical simulation of vibration characteristics of hydrofoil in cavitating flow

The unsteady cavitation behaviour and the corresponding cavity induced vibrations were investigated. The high-speed camera and a single point laser Doppler vibrometer (LDV) are used to ana-lyze the transient cavitating flow structures and the corresponding structural vibration characteristics. The k-ω SST turbulence model with the turbulence viscosity correction and the Zwart cavitation model are introduced to the simulations. The fluid model is coupled with a chordwise rigid, two degrees-of-freedom system with the hybrid coupled fluid structure interaction model. The results show that the maximum vibration amplitude keeps relatively small for the inception cavitation and sheet cavitation, increases dramatically for the cloud cavitation and declines for the supercavitation. The main flow-induced frequency, which is in accord with the cavity shedding frequency, reduces with the decreasing of the cavitation number. Owing to the disturbance caused by the flow-induced flutter and deformation of the foil, it presents more complex cavitation patterns for the flexible hydrofoil, as well as more components in the vibration spectra.