Effects of static pressure changes on cavitation bubble dynamics and sonoluminescence

Abstract The effects of static pressure changes on sonoluminescence (SL) were investigated. An increase in static pressure increased SL intensity. During the initial bubble growth phase, the increase in static pressure delayed bubble growth but suppressed clustering, resulting in higher SL intensity. Bubble size decreased with increasing static pressure. Numerical calculations showed that increased static pressure shortened bubble collapse time, thereby affecting the primary Bjerknes force acting on the bubble. The increased static pressure allowed the bubble to approach regions of higher sound pressure in the standing wave. The reduction in bubble size and the change in trapping position due to increased static pressure contributed to an increase in bubble internal temperature and were factors that increased SL intensity.