Reconstruction And Prediction Of Sound Field In Limited Space Based On Equivalent Source Method

Submarine,aircraft and other cabin environment is a closed limited space.The reconstruction and prediction technology of sound field in the limited space is of great significance for cabin sound field visualization,cabin noise source identification and noise testing.However,the sound field in the limited closed space is a strong reverberation field,which brings great difficulty for cabin sound field reconstruction and prediction To carry out the research of sound field reconstruction and prediction in limited space based on equivalent source method.In this paper,the finite space sound field formed by the excited vibration of cylindrical shell is taken as the research model,and the reconstruction and prediction method of the finite space sound field based on the equivalent source method is studied.Based on the normal mode theory and the thin shell theory,the finite space sound field formed by the excited vibration of cylindrical shell is theoretically studied,and the vibration model of the cylindrical shell with two ends simply supported under the force excitation is established The finite element software COMSOL is used to calculate and analyze the sound field distribution in the cylindrical shell under the force excitation.The correctness of the model is verified by comparing with the analytical solution,and the spatial distribution characteristics of the sound field in the cylindrical shell under the force excitation are analyzed.In order to solve the problem of sound field reconstruction and prediction in confined space,a theoretical model of sound field reconstruction and prediction in confined space based on equivalent source method is established,and numerical simulation analysis is carried out to verify the correctness of the finite space method based on equivalent source method.The reconstruction and prediction performance of equivalent source method in confined space under different regularization parameter selection methods is discussed,The results show that the equivalent source method has the best performance in sound field reconstruction and prediction under the regularization parameter selection method based on Bayesian criterion;the finite space sound field prediction based on the equivalent source method is realized respectively based on the cylindrical array with microphone at both ends,the cylindrical array without microphone at both ends and the spherical array.The results show that the equivalent source method based on the cylindrical array with closed ends is effective Compared with the cylindrical near-field acoustic holography transform,the finite space acoustic field reconstruction and prediction performance is the best.The results show that the finite space acoustic field reconstruction and prediction method based on equivalent source method has higher accuracy,and the applicability of cylindrical near-field acoustic holography transform is poor.The equivalent source method is discussed in detail The results show that the selection of the equivalent source surface,the mesh refinement of the equivalent source surface,the position of the holographic surface and the number of measurement points affect the performance of the finite space acoustic field reconstruction and prediction method based on the equivalent source.In this paper,based on the submarine cabin model,the experimental research of sound field reconstruction and prediction in the limited closed space is carried out.The vibration of the cabin shell is excited by force,and the sound pressure data on the holographic surface,reconstruction surface and prediction surface are obtained by using the double cylindrical scanning array measurement.Through the experimental data processing and analysis,the correctness and feasibility of the method of sound field reconstruction and prediction in the limited space based on the equivalent source method are verified Compared with the reconstruction and prediction performance of cylindrical near-field acoustic holography,the reconstruction and prediction performance of the two methods at different frequencies are analyzed.The experimental results are consistent with the simulation results.