典型活塞换能器声场分布及其指向性

Investigation on sound distribution and directivity of typical piston transducer

为了比较分析形状各异的声源声场分布及指向特性,利用瑞利积分和加法定理,计算出5种典型活塞声源辐射声场的远场声压分布和指向性函数,分析了辐射频率和几何尺寸对指向性的影响,并采用MATLAB进行二维及三维的仿真模拟。结果表明,方形(环)活塞的指向性要好于等面积的圆形(环)活塞的指向性;在活塞尺寸不变的情况下,频率增大,所有形状活塞换能器指向性均增强;当频率和外径不变时,内径尺寸对环形活塞指向性影响较小;当频率和内径不变时,外径越大,环形活塞指向性越好。

The emphasis of phased array focusing technique is to analyze the acoustic field characteristics ofany single array element. Piston transducer has many models, such as circular piston, ring piston, rectan-gular piston, square piston, quadrate ring piston and so on. Five typical piston transducer models weresimulated in order to analyze their acoustical field and compare their directivity. The far-field sound pres-sure distribution and the directivity function were calculated using Rayleigh equation and the addition theo-rem. Two and three dimensional directivity of the piston source were simulated by M-language of MAT-LAB simultaneously. Several directionality related factors were also analyzed. The result shows that at thesame value of frequency and piston area, the far field of the square （quadrate ring） piston is more uniformthan that of the circular （ring） piston. In the case of constant piston size, the directivity of all pistontransducers 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）.