Prediction and experiment for nearfield sound radiation of cylindrical shells

It is difficult to calculate and measure the near-field sound radiation which caused by structure vibration of the complicated cylindrical shell. The wave decomposition method and wave superposition method were applied to predict the near-field pressure. The surface normal vibration velocity and near-field pressure of simple cylindrical shell were applied to research the prediction effect. According to the analytic computation results,the predicted results affected by different pre-measured surfaces and array number were analyzed with the wave decomposition method,and the predicted results affected by different fictitious source positions and array number were analyzed by the wave superposition method. The results show that the wave decomposition performance is better at the large number of the accelerometer,but when the accelerated array number is relative few,the method is inferior to the wave superposition method. The performance of the wave superposition method is influenced by the position of the fictitious source,and the distance between the fictitious source and the surface accelerometer has an optimum value. The experiments on the measurement of the normal vibration velocity and near-field pressure of simply cylindrical shell under water were done,and the comparison between the predicted results and the experimental results proved the conclusions.