Abstract
Ultrasound energy losses due to viscosity in a fluid induce acoustic streaming globally and elevate temperature locally. Generally, the flow induced in the beam reduces the elevation of temperature by cooling. The present report seeks to clarify the cooling effect of streaming on the ultrasound heating in three kinds of fluid with different viscosities. Numerical examples of the streaming velocity and temperature elevation are given along and across the beam axis for a Gaussian focusing system. The effect of buoyancy on the generation of acoustic streaming is usually neglected. However, the streaming significantly changes the spatial distribution of the temperature, in particular, in a fluid with high viscosity.
