声空化泡对声传播的屏蔽特性

Cavitation bubbles screen the acoustic propagation

该文介绍了声空化液体中声波被反常吸收的现象,即驱动声压越大,吸收越强,远场声压越低。研究给出其物理机理是高声压导致强空化,空化泡吸收驱动能量辐射高次谐波,高频声波更易被液体吸收,最终形成更低的远场声压。为了克服空化屏蔽,改善声空化的均匀性,提出了改变工作液体的空化阈值的思路。并就简单的双层液体系统进行了计算和实验,结果证实这种思路的正确性。

An abnormal absorption of sound has been reported in cavitation screening.The stronger driving sound is,the lower output we gets in far-field.The physical mechanism is that(i)the higher driving sound makes liquid be stronger cavitation,(ii)the pulsation of cavitation bubbles transfers energy from the fundamental to harmonics,and(iii)the stronger absorption from the liquid for the harmonics causes the output sound is lower finally.For overcoming the cavitation screening and homogenizing the cavitation,an approach with the changing cavitation threshold of the host liquid has been proposed.And its feasibility has also been proved by the numerical simulation and experiment based on a simple two-layer liquid model.