Response of an ultrasonically excited bubble near a fixed rigid object

Various independent studies suggest that echo-contrast agents can increase the likelihood of ultrasonic bioeffects. To better understand bioeffects involving cavitation, a two-dimensional boundary element model was used to simulate ultrasonically excited bubble behavior near a rigid object, either a plane, sphere, or disk, the approximate size of a red blood cell. As the distance between the object and bubble increases, the bubble collapse becomes more spherically symmetric, producing higher maximum bubble pressures. Pressure and velocity fields around a bubble collapsing near a rigid disk are compared for two distances, demonstrating differences between more spherically symmetric and asymmetric bubble collapses.