Numerical Simulation of Focused Ultrasound Wave Propagation in Bubbly Fluid Using Equation of Sound Wave

Abstract

Numerical simulation method of High Intensity Focused Ultrasound (HIFU) propagation in bubbly fluid (microbubbles in liquid) is proposed for observing the ultrasound wave propagation, the bubble motion at focal area and the ultrasound power at the focal point in this paper. The governing equations are the acoustic wave equation derived from the equation of fluid and the Keller equation (bubble volume motion equation). These equations are discretized by the finite difference method. Additionally, the linear dispersion relation is derived from governing equations. First, the present method is validated on grid convergence and compared with experiment and theory. Second, HIFU in bubbly fluid is simulated for various initial void fraction and bubble radius to observe the difference of pressure field and difference of bubble motion.