Theoretical and Experimental Investigation of Cylindrical Liquid-Filled Acoustic Lenses with D/lambda Ratios Greater Than 15

摘要

Focusing properties of liquid-filled cylindrical acoustic lenses are investigated theoretically and experimentally for d/lambda ratios greater than 15. A mathematical model which includes the effects of the lens shell is described and used to predict directivity patterns. Based on this model, a right-circular cylindrical lens, 40 cm in diameter, was constructed and tested at frequencies ranging from 25 to 900 khz. Agreement of experimental directivity patterns with those predicted demonstrated feasibility of the lens at d/lambda ratios up to 150, a factor of 10 greater than previously reported. Theoretical investigation indicates that for d/lambda ratios greater than 150 the elliptical cylindrical lens shows promise, but fabrication of an experimental model is yet to be undertaken. (Author)