The Research On Flow-induced Vibration And Noise Characteristics Of Sail-struct Model

The envelope shell of command cobinet is a symbolic and streamlined permeable structure highlighted on the surface of a submarine.With the more effective control on mechanical noise and propeller noise of many countries, the noise radiation of the command sets under the impact of the water flow has increasingly caused more and more concerns. This article at first simulated the flow field of two-dimensional and three-dimensional command sets by large-scale computational fluid dynamics software (CFD), studied the pressure and flow field along the shell surface, whose results provide the foundation for the next structural optimization. Then, modes of the sail model have been analyzed, and according to the modal analysis results, several optimization schedules have been proposed. With the method of finite element+indirect boundary element, this paper calculated the radiated sound power for the model before and after optimized, and analyzed the noise reduction effect for all the optimized schedules. According to the numerical results, several experimental sail models have been built up, and the radiated power of the models has been measured by reverberation method in gravity water tunnel.The results from the numerical calculation and experimental measurement show that the flow noise can be reduced greatly after the sail model has been optimized properly. The flow noise of the sail model is related to the flow speed, and the total radiated sound power from the sail model is roughly proportional to the 4.9-6.3 power of the flow speed, which is consistency to the general law of fluid-noise.