The Flow-induced Vibration And Acoustic Characteristics Analysis On The Underwater Small Vehicles In High Speed

Compared with mechanical noise and propeller-radiated noise, the flow-induced vibration noise constitutes the main part of radiated noise of the underwater small vehicles in high speed of dozens of Knot. The research of flow-induced vibration noise is essential for increases the small vehicles and their launch platform stealth characteristics. The flow-induced vibration noise is mainly from the boundary layer produced by the contact between the surface out of the small vehicles and the water. The early theoretical analysis of the flow-induced vibration noise mainly according to half theory and half experience,recently, we can stimulate the flow and sound field accurately and conveniently by the computer simulation method benefit the development of finite element analysis and CFD technique.The main content of this paper: Firstly,designed four underwater vehicles with different linetypes according to the linetypes of active-duty small vehicles in high speed and performed the mode analysis and the flow and sound field calculation by the advanced software. Establish the four model by SolidWorks. Perform the mode analysis of the structural vibration and fluid-solid coupling vibration for the four underwater vehicles.Establish the flow field model for calculation of fluid field and sound field model for calculation of sound field utilized the method of finite element analysis software and processed with the discrete way. Simulate and calculate the performance of fluid field for different kinds of linetypes at three velocity of flow from different turbulence model utilized the k-ε model in the two Reynolds average methods and CFD software. Obtain the]ow-induced vibration noise for different models and flow utilized the Lighthill sound analogous theory to simulate and calculate the low-induced vibration noise of models, the stimulated source for sound field analysis software is the pressure fluctuations in turbulent flows obtain from the previous step.Then machined the four kinds of model and measured respectively in the water tunnel of low noise by the reverberation tank method. Finally compared and analyzed the simulation results and the date acquired from the water tunnel.The simulation results show that: for the underwater small vehicle, the flow-induced vibration noise increased with increasing water flow and the pressure fluctuations in turbulent flows of the head of the model is higher than other positions;the flow-induced vibration noise of the flatheaded model is higher than the bulletheaded model with the same head length; for flatheaded models, the long size have a lower flow-induced vibration noise.To verify these simulation results, the radiate noise measurement for the four models were carried out in the gravity water tunnel of low noise in Harbin engineering University.The results based on the experiment data are agree with the simulation results. This can certify the simulation method has high accuracy.