Numerical Study Flow-excited Noise Of Submarine Based On Joint Simulation

The velocity fluctuation in turbulence and fluctuating pressure on solid boundaries are acoustic quadruples and dipoles respectively,which comprise of flow noise.The fluid structure coupling cause structural vibration,the noise value of flow noise will increase,the noise generated by structural vibration and dipole noise constitute the flow-excited noise.Submarine's concealment is an important performance index of submarine.Flow-excited noise seriously weakens the submarine's concealment,so it is of great significance to study the generation and characteristics of flow-excited noise.Firstly,combined with RNG k-? turbulence model,the flow field around submarine called SUBOFF is calculated.The numerical solution is compared with experimental data,which validates the CFD numerical simulation.Then the cone-column combined submarine structure is taken as the research object,and the flow noise of the submarine at a series of monitoring points is calculated by using the Lighthill acoustic analogy theory FW-H equation.Secondly,the submarine structure is an elastic body that will undergo fluid-solid coupling,but the fluid-structure coupling cannot be completed by STAR-CCM+.So,ABAQUS is used to calculate the vibration displacement caused by pulsating pressure,and the change of the flow field caused by the vibration displacement is recalculated in STAR-CCM+.The co-simulation of the two software is used to calculate the flow-excited noise at different incoming velocity,and compared with the experimental data,which proved that the joint simulation calculation of flow-induced noise is very reliable.The flow-excited noise at the same monitoring point as flow noise is calculated with the joint simulation.The results show that flow-induced noise at the same frequency is greater than that of flow noise.Finally,this paper focuses on the flow-excited noise.The effects of different flow velocities,different thicknesses and materials on the flow-excited noise at various monitoring points were studied.The results show that the increase of the flow speed will increase the flow-excited noise;Increasing the thickness of the submarine shell will make the rigidity of the submarine structure smaller and the vibration amplitude smaller,thus reducing the flow-excited noise;By calculating the three materials of ordinary steel,aluminum alloy and titanium alloy,the change of material will also cause the change of flow-excited noise.