Abstract: Considering the heat loss and viscous loss in the acoustic boundary layer,a two-dimensional acoustic streaming calculation model of a spherical particle at the sound pressure node of a plane standing wave is established,and the numerical method of separation time scale is used to simulate the characteristics of the acoustic streaming field outside the particle.The reliability of the numerical simulation is verified by comparing the simulation results with the corresponding analytical solution and experimental results.On this basis,the effects of Reynolds number Re and Strouhal number Sr on the second-order acoustic streaming field structure,vortex intensity and range in the spherical particle acoustic boundary layer are studied.The results show that with the increase of Sr and Re,the scale of the vortex structure in 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,and 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.