空气耦合超声换能器声场的时域计算方法

An approach to compute transient acoustic field radiated by air-coupled transducer

通过超声波在空气中的二次方衰减特性,推导出空气中时域格林函数的解析表达式。基于该函数和瑞利积分建立了空气耦合超声换能器时域声场的快速计算模型,并对圆形换能器声场进行仿真。结果表明,相对于无衰减介质,空气中时域信号的高频成分被极大地削弱,信号幅值随传播距离的增加而明显降低,轴向近场长度明显减小。该研究为空气耦合超声换能器声场的模拟提供了快速的计算方法,研究结果对于空气耦合超声换能器的设计和校准具有参考价值。

A time-domain analytical Green′s function was proposed for air which is characterized by quadratic attenuation.Based on the function and Rayleigh′s integral,a time-domain model was created to compute transient acoustic field radiated from circular piston into air.The simulation shows that compared with non-attenuation case,in air,high frequency component is greatly weakened,an evident drop as a function of wave propagation distance is found in signal amplitude,and a decrease is observed in near-field length.The study provides a fast computing approach for the air-coupled acoustic field simulation.At the same time,it presents a good reference for air-coupled transducer design and calibration.