Abstract
The interactions between bubbles and ultrasound in a blood vessel are investigated numerically by using the boundary element method (BEM). The blood vessel is modeled by an elastic tube with spring-mass system. The dynamics of two bubbles in the tube are simulated successfully by considering the three-dimensional deformations of the bubbles. It is shown that when one bubble is initially located on the axis of the tube and the other is not on the axis, the translation toward the side wall of the tube causes the inclined liquid jet formation on the bubble surfaces. A heavier mass of the side wall leads to a longer period of bubble oscillations because the natural frequency decreases with increase in the mass. A simple bubble model for investing bubble oscillations in the tube is also introduced and is combined with the spring-mass system of the tube: the bubble is represented by the point source for the bubble volume oscillation and the dipole for the translational motion. The result using the bubble model is in good agreement with that obtained from the fully three-dimensional BEM calculation.
