In order to better understand the contribution of bubble collapse
to stone comminution in shockwave lithotripsy, the shockinduced
and Rayleigh collapse of a spherical air bubble is investigated
using numerical simulations, and the free-field collapse of
a cavitation bubble is studied experimentally. In shock-induced
collapse near a wall, it is found that the presence of the bubble
greatly amplifies the pressure recorded at the stone surface; the
functional dependence of the wall pressure on the initial standoff
distance and the amplitude are presented. In Rayleigh collapse
near a solid surface, the proximity of the wall retards the
flow and leads to a more prominent jet. Experiments show that
re-entrant jets form in the collapse of cavitation bubbles excited
by lithotripter shockwaves in a fashion comparable to previous
studies of collapse near a solid surface
