Analysis of the hydrodynamic damping characteristics on a symmetrical hydrofoil

Abstract Hydrodynamic damping is a key factor that influencing the amplitude of structural vibration under resonance conditions. In this study, the one-way FSI energy balance method by loading structure mode onto flow field is applied to simulate the hydrodynamic damping. Based on the good solution of vortex shedding frequency, structure natural frequency and mode shape, it provides a good accuracy on both flow field and structural field by predicting the hydrodynamic damping well with deviations less than 10.4%. On the basis, the hydrodynamic damping characteristics of different vibration displacements and the lock-in region are studied and analyzed in detail. Results found that the hydrodynamic damping ratio increases with the increasing of vibration displacement. A displacement interval within 6 × 10−5 m–1.2 × 10−4 m can be detected when the hydrodynamic damping ratio is slightly affected by vibration displacement. It is proved that the value of hydrodynamic damping depends on the combined area of hydrodynamic force and structural velocities. The hydrodynamic damping in the lock-in region changes nonlinearly. Under the resonance condition, the disturbance of the fluid domain increases, and a negative damping value will appear, which will increase the structure vibration amplitude.