Numerical simulation of acoustic streaming distribution outside spherical particles under the action of sound waves

Considering the heat loss and viscosity loss inside the acoustic boundary layer,an acoustic streaming calculation model outside a two-dimensional spherical particle at the sound pressure node of a plane standing wave is established,and the numerical method of the separation time scale is used to simulate the characteristics of the acoustic streaming outside the particle.The reliability of the numerical simulation is verified by comparing the simulation results with the corresponding analytical solution and experimental results.Thus,the effects of Reynolds number Re and Strouhal number Sr on the acoustic streaming structure,vortex intensity and range inside the acoustic boundary layer are studied.The results show that with increases in Sr and Re,the scale of the vortex structure inside the acoustic boundary layer decreases exponentially,which is inversely proportional to the particle diameter and the excitation frequency,and directly proportional to the kinematic viscosity of the fluid medium;additionally,the acoustic vibration system with low Sr and high Re can form a larger range and stronger acoustic streaming.The numerical method can be used to evaluate the external acoustic streaming characteristics of any physical model.