Experimental and computational evaluation of surface geometry effects on underwater acoustic beam shaping with...

This paper examines how radiating surface structure can influence the properties of beam-shaping of the piezoelectric piston type underwater acoustic transducers. The study is done using a broad theoretical, numerical and experimental method. This study presents a comprehensive analysis of the far-field radiation characteristics of circular, square, hexagonal, and octagonal piston-type ultrasonic transducers for underwater applications. The models were validated with three-dimensional finite element simulations and experimental measurements using a wafer Tonpilz transducer prototype. This analysis demonstrates that piston geometry has no significant effect on radiation characteristics for small apertures whose Equivalent Circular Diameter (ECD) is less than half the wavelength. The circular piston is found to exhibit superior performance at increased apertures. Result shows that circular pistons provide superior beam uniformity, narrow main lobes, and low side-lobe levels, making them highly efficient for focused energy transmission, sonar, and underwater communication systems. Experimental validation is provided only for the circular case, while theoretical and numerical results are presented for all pistons. This control of the beam makes the circular piston the solution to accurate acoustic control. Finite element analysis and experimental measurements on a circular wafer transducer proved the validity of the theoretical models. This high level of agreement validates that the findings can directly applied to designing advanced underwater acoustic arrays.