Far field directivity of built-up circumference array of circular piston sound source

A built-up circumference array of circular piston sound source was designed to get higher directional sound source.The directivity function of the sound source was derived applying the directive theory of multiplex system.The results indicate that the sound source has directivity at any acoustic frequency and uniform radiation is at far sound field.The directivity characteristic gets stronger when acoustic frequency is higher and the number of pistons is more.The directivity characteristic enhances correspondingly when piston radius increasing while keeping the frequency constant.Compared with the single piston sound source and the built-up rectangle array piston sound source,the sound source has higher directivity characteristic.Tests on circumference underwater projecting transducer which was designed by using six pieces of PZT-4 piezoelectric ceramic chips as piston elements show the validity of the design.The experimantal results have good matching with the theoretical results.