Vibration Mode And Sound Field Analysis Of Noise Monitoring Subsurface Buoy

Subsurface buoy system can be placed in seawater for a long time according to its stable performance.It is a good ocean observation system to collect the information of hydrological monitoring,tidal change,weather forecast,crustal movement and so on.In this paper,the subsurface buoy noise monitoring is taken as the research object,and the vibration mode and flow noise of the noise monitoring substandard are analyzed and studied.Firstly,the vibration mode of the standard structure is tested and simulated.The simplified 3D model of the subsurface buoy frame is established by using the 3D modeling software Pro/E,and then the dry and wet vibration modes of the subsurface buoy structure are simulated and analyzed by Ansys Workbench,and the data are compared after the experiment in indoor and still water tank.The rationality of the numerical simulation method for wet modal analysis is verified.By using the finite element method to analyze the dry and wet modes of the subsurface buoy-frame,the difference between the dry and wet modes can be clearly seen,which proves the necessity of wet modal analysis of underwater structures.According to the comparison and analysis of the simulation and experimental results,the original subsurface buoy system is improved,which makes the vibration mode of the subsurface buoy structure avoid its 10-100Hz working frequency band and improves the performance of the subsurface buoy system.Secondly,four kinds of subsurface buoy models,spherical,spherical,elongated,conical and water drop,are established respectively,and the flow field and sound field of subsurface buoy are analyzed.Fluent is used to simulate the flow field and sound field of the external diversion cover.The RNG fluid model and the large eddy fluid model are used to simulate the flow field of the outer diversion cover under steady and unsteady flow,respectively.The flow noise of the outer diversion cover is analyzed by using the FW-H acoustic model.The underwater experiments are carried out,and the experimental results are compared with the simulation results.The calculation results show that the water droplet type subsurface buoy is the best.The results show that the profile line is the main cause of the difference in the noise performance.In the design of subsurface buoy noise monitoring,the flow noise can be significantly reduced by improving the profile characteristics.