驻波声场中悬浮临界密度及稳定性研究

Study of the critical density and stability of suspension in standing wave sound field

本文以声场中物体为研究对象,理论上得到行波和驻波场中的声辐射压力方程.在驻波声场中引入临界悬浮密度概念,可作为物体能否在非线性声场中悬浮的判据,同时给出谐振腔移动速度的最大范围.更进一步,以实验参数作为数值计算的输入来指导实验,并结合实验结果讨论了驻波声场中样品密度和大小、发射面和反射面形状以及两者之间的距离、反射面的尺寸等因素对物体悬浮稳定性的影响,发现当物体尺寸和密度确定时,调控好谐振腔的长度,增加波腹处的声压是提升声悬浮稳定性的有效手段.

In this paper, the object in the sound field is studied, and the acoustic radiation pressure equation is theoretically derived both in the travelling wave and the standing wave. The concept of the critical suspension density is introduced into the standing wave sound field, which should be used as a criterion for suspension in a nonlinear sound field. At the same time, the maximum range of Resonant cavity’s movement speed is given. Furthermore, by the combination of numerical computations and experimental results, the influence of the density and the size of the sample in the standing wave sound field, the shape of the emitting surface and the reflecting surface, the distance between these two surface, and the size of the reflecting surface on the suspension stability are investigated. It is found that when the size and the density of the object are determined, adjusting the length of the resonant cavity and increasing the sound pressure at the antinode are effective means to improve the acoustic suspension stability.