| Echo characteristics of a regular corrugated(sine squared curve)surface sphere ant its derived models in water with a incident plane wave is investigated by using the planar elements method,which is used for forecasting echo characteristics of sonar targets,and the finite elements method.The effects of surface corrugation’s height,period,the number of peak and dip,incident plane wave frequency and incident azimuth angle on the spatial distribution and frequency response characteristics of acoustic target strength are analyzed.The mechanism of the formation of spatial distribution characteristics of target strength in different frequency bands is discussed.The approximate quantitative relationship between the parameters of corrugated surface and the spatial distribution as well as frequency response characteristics of target strength is obtained.Echo characteristics of a nonrigid regular corrugated(sine squared curve)surface sphere in water with a incident plane wave is investigated by using the nonrigid planar elements method.The target strength of the 3D printed regular corrugated surface nylon sphere is measured in acoustic tank.The measured spatial distribution and frequency response characteristics of target strength are in good agreement with the theoretical computed results.A thorough understanding of the echo characteristics of regular corrugated surface sphere is helpful to carry out research on controlling the scattering sound field by using the acoustic metamaterials. |
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