可移动准刚性圆柱对平面波的声散射

Acoustic Scattering of a Movable Quasi-rigid Cylinder for Plane Wave

计算了可移动的无限长圆柱体对于平面波的散射声场,并推导了圆柱表面的受力情况以及散射声场的方向性函数.以相对于空气可以看成准刚性材料的聚苯乙烯泡沫为例,根据理论结果进行了数值仿真模拟.研究表明:散射声场的方向性与入射声波的频率相关,频率越高,方向性越强,在低频时与固定圆柱有较大不同,高频时趋于一致;圆柱表面受力存在峰值,并且在峰值处与固定圆柱有明显差异.该研究结果消除了传统理论中关于散射体固定不动的限制,为实际中运动目标的识别以及缺陷的定位等提供了必要的理论依据.

The scattering sound field of a movable infinite cylinder for plane waves was calculated theoretically,and the force on the surface of the cylinder and the directivity function of the scattering sound field were derived.Taking the polystyrene foam which can be regarded as quasi-rigid material relative to air as an example,numerical simulation was carried out based on the theoretical results.The results showed that the directivity of the scattering sound field was significantly related to the frequency of the incident sound waves.The higher the frequency,the stronger the directionality.It was quite different from the fixed cylinder at low frequencies,while tended to be consistent with each other at high frequencies.There was a peak force on the surface of the cylinder,which was significantly different from that of the fixed cylinder at the peak.The research results eliminated the limitation of the fixity of the scattering object in the traditional theory,and provided the necessary theoretical basis for the identification of moving targets and the location of the defects in practice.