摘要
考虑介质的衰减及其引起的频散对频域声场的影响,提出幂函数衰减介质中圆形换能器声场的解析公式。基于该公式研究空气耦合超声换能器的轴向声压与径向声压分布特征。结果表明:空气中的衰减是引起声场变化的主要因素;相对于零衰减介质,空气中的声压幅度随着传播距离的增加而明显降低,近场长度明显减小,近场内轴向声压的零点、极大值点无偏移,径向声压分布和声束扩散角无变化。研究结果对于空气耦合换能器的设计、空气耦合声场的测量、校准具有重要参考价值,并可以作为ASTM E1065/E1065-14和IEC 62127标准的补充。
The influence of medium attenuation and the associated dispersion is considered of acoustic field in frequency domain.An analytical solution for the acoustic field radiated from circular ultrasonic transducer into lossy medium with power law attenuation is proposed. Based on the solution, a research on the axial-and radial-acoustic pressure distribution of air-coupled transducer is performed and it shows that: attenuation is the main factor causing acoustic field distortion in air; compared with non-attenuation case, in air, the amplitude of acoustic pressure drops down evidently as a function of propagation distance, the near-field length decreases, the zero-and maxima-points in near-field stay the same, the shape of directivity pattern and beam spread angle have no difference. The result is a good reference for the design of air-coupled transducer and the corresponding acoustic field measurement and calibration; as well it could be a compliment of transducer characterization standard ASTM E1065/E1065-14 and IEC 62127.
引文
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