Investigation on sound distribution and directivity of typical piston transducer

Abstract

The emphasis of phased array focusing technique is to analyze the acoustic field characteristics of any single array element. Piston transducer has many models, such as circular piston, ring piston, rectangular piston, square piston, quadrate ring piston and so on. Five typical piston transducer models were simulated in order to analyze their acoustical field and compare their directivity. The far-field sound pressure distribution and the directivity function were calculated using Rayleigh equation and the addition theorem. Two and three dimensional directivity of the piston source were simulated by M-language of MATLAB simultaneously. Several directionality related factors were also analyzed. The result shows that at the same value of frequency and piston area, the far field of the square (quadrate ring) piston is more uniform than that of the circular (ring) piston. In the case of constant piston size, the directivity of all piston transducers increase with frequency increased. When both frequency and outside radius (side) are fixed, the inside radius (side) has little effect on the directivity. However, at the same frequency, while the inside radius (side) remains unchanged, the directivity intensifies obviously with the increase of the outside radius (side).