基于角谱法分析圆形活塞声源近场声特性

Study on Near Field Sound Pressure of Circular Piston Sound Source Based on Spatial Fourier Transfor

圆形活塞的声辐射应用较广,大多数超声检测应用中所用的声源,都可视为活塞式辐射器。利用角谱法分析了传播波和倏逝波在声场轴线上的分布与空间位置、声源半径及辐射频率间的关系,通过比较两种波的声压幅值确定了倏逝波的有效传播距离。利用近场声全息(NAH)理论计算了倏逝波在换能器近场空间的声压分布,并对结果进行误差分析。仿真结果表明,基于空间傅里叶变换的角谱法和NAH法均可准确反映圆形活塞辐射近场声压呈现数衰减的分布规律。

The circular piston sound radiation has wide applications.Most of the sound sources for the ultrasonic detection can be considered as the piston radiators.The relationship among the distribution and space position of the propagation wave and evanescent wave on the axis of sound field,the sound source radius and the radiation frequency is analyzed by the angular spectrum method.The effective propagation distance of the evanescent wave is determined by comparing the sound pressure amplitudes of two kinds of waves.The near field acoustic holography(NAH)theory is used to calculate the sound pressure distribution of the evanescent wave in the near field space of the transducer,and the error analysis is also carried out.The simulation results show that both the angular spectrum method and the NAH method based on the spatial Fourier transform can accurately reflect the distribution law that the near field sound pressure of the circular piston radiation is presented exponential decay.