Ovchinnikov Mikhail, Zhou Jianbo, Yalamanchili Satish
Alcon Research, LTD., 20511 Lake Forest Drive, Lake Forest, California 92630.
J Acoust Soc Am. 2014 Jul;136(1):22-9. doi: 10.1121/1.4881919.
Anomalous acoustic streaming is observed emanating from sharp edges of solid bodies that are vibrating in fluids. The streaming velocities can be orders of magnitude higher than expected from the Rayleigh streaming at similar amplitudes of vibration. Acoustic velocity of fluid relative to a solid body diverges at a sharp edge, giving rise to a localized time-independent body force acting on the fluid. This force results in a formation of a localized jet. Two-dimensional numerical simulations are performed to predict acoustic streaming for low amplitude vibration using two methods: (1) Steady-state solution utilizing perturbation theory and (2) direct transient solution of the Navier-Stokes equations. Both analyses agree with each other and correctly predict the streaming of a sharp-edged vibrating blade measured experimentally. The origin of the streaming can be attributed to the centrifugal force of the acoustic fluid flow around a sharp edge. The dependence of this acoustic streaming on frequency and velocity is examined using dimensional analysis. The dependence law is devised and confirmed by numerical simulations.
在流体中振动的固体尖锐边缘会产生异常声流。其流速可能比在类似振动幅度下瑞利流预期的流速高出几个数量级。流体相对于固体的声速在尖锐边缘处发散，从而产生作用于流体的局部与时间无关的体力。该力导致形成局部射流。采用两种方法进行二维数值模拟以预测低振幅振动下的声流：（1）利用微扰理论的稳态解；（2）纳维-斯托克斯方程的直接瞬态解。两种分析结果相互一致，并正确预测了实验测量的尖锐边缘振动叶片的声流。声流的起源可归因于尖锐边缘周围声流体流动的离心力。使用量纲分析研究了这种声流对频率和速度的依赖性。通过数值模拟设计并验证了相关依赖定律。
