Numerical Study Of Flow-induced Vibration And Noise Of Hydrofoil Based On Co-simulation

Hydrofoil structure is widely used in the field of ships and marine engineering.With the development of ships to high-speed,its hydroelastic vibration and safety problems cannot be ignored,and will increase hydrodynamic noise and weaken the acoustic stealth performance of underwater vehicles.In view of the above engineering background,the flow-induced vibration characteristics and noise of hydrofoil are numerically simulated in this paper.In this paper,the co-simulation framework of hydrofoil flow-induced vibration is firstly established based on computational fluid dynamics method and structural finite element method.The flow field around the hydrofoil is solved by Star-CCM + software using finite volume method,and the structural vibration is solved by Abaqus software using finite element method.The fluid load and structural displacement are transmitted on the fluid solid interface to realize fluid structure interaction.The method is applied to predict the flow-induced vibration response of flexible cantilever hydrofoil,and the reliability of the method is verified by comparing with the experimental results.Then,the heave and torsional vibration responses of 2-DOF hydrofoil under uniform flow were simulated.The results show that when the inflow velocity increases to a certain critical value,the hydrofoil will enter the flutter critical state without amplitude attenuation.A small change of the initial attack angle has a great influence on the vibration amplitude,but the frequency is basically unchanged.The natural frequency ratio and inertia radius of the hydrofoil can affect the critical flutter speed.Secondly,the flow-induced vibration and acoustic radiation of a flexible hydrofoil are studied in this paper.The flow field is calculated by large eddy simulation.Taking the vibration response obtained by fluid structure interaction as the boundary condition,combined with Abaqus acoustic-solid coupling method,the vibration radiation noise of hydrofoil is predicted.It is found that the frequency of vortex shedding increases with the increase of flow velocity.When the frequency is close to the first-order torsional natural frequency of the hydrofoil,the amplitude of vibration response and the sound pressure level of radiation noise increase significantly,and the vortex force and wake strength increase greatly.Finally,based on FW-H acoustic analogy and acoustic-solid coupling method,the variation of flow noise and vibration radiation noise of underwater vehicle bow rudder at different flow velocities and attack angles are studied.The results show that the flow noise of the bow rudder increases with the increase of the flow velocity.The sound directivity on the cross section at different attack angles is 8-shaped,and the amplitude-frequency characteristics are similar to the hydrodynamic results.The flow-induced vibration amplitude of the bow rudder is mainly affected by the first three modes.The vibration amplitude increases with the increase of flow velocity,but the contribution of each mode is different under different attack angles.The flow-induced vibration noise of the bow rudder increases with the increase of the flow velocity,and the attack angle will affect the acoustic directivity shape.The amplitude-frequency characteristics are similar to the vibration acceleration spectrum.