Numerical Simulation Of Flowand Flow Noise For Submerged Bodies With Cavities

Firstly, we took the two-dimensional inverted "T" type cavity as the research model and carried out numerical flow and flow noise simulation based on large eddy simulation (LES) method and Lighthill acoustic analogy theory with the general CFD software FLUENT. Then we probed into the mechanism of cavity flow noise, and compared the computed results with the published experimental data from open reference. The comparison showed that the computed results agree well with the experimental data and so verified the validity of simulating the flow-induced noise with software. In this way, a reliable numerical method was put up forward..Based on the work mentioned above, using the SIMPLE algorithm (Semi Implicit Method for Pressure Linked Equations) combined with RNGk-εturbulence model, we carried out three-dimensional numerical simulations on steady flows around three submerged bodies, the bare one without cavity, the prototype with original cavities and the type with modified cavities. When the steady computation converged, we took the steady result as the initial data to launch unsteady computation based on LES turbulence model. When the unsteady computation tended to be stabilized, loaded the FW-H (The Ffowcs Williams and Hawkings Acoustic Model) acoustic module to start the flow-induced noise simulation. At last we made use of the post-processing module of FLUENT to process the sound signal and got the acoustic radiation results both in the near-field and far-field around the bodies.Through the analysis to the flow and flow noise around these bodies, we found that the modified one had the lower resistance and flow noise than the prototype as the expectation.The comprehensive analysis of flow and flow noise show that the large eddy simulation method could simulate turbulence oscillation preferably, and is an accurate model for unsteady flow numerical simulation and can be used to compute flow noise. The numerical simulation method of flow noise can supply the theoretical support for the optimal design of cavities of submerged bodies.