 ?Stability map and energy focusing of sonoluminescent bubbles in sulphuric acid for different static pressures?

JUAN MANUEL ROSSELLO,; DAMIAN DELLAVALE; BONETTO, FABIAN

Workshop; ?XIII Latin American Workshop on Nonlinear Phenomena (LAWNP; 2013

Single bubble sonoluminescence (SBSL) is a two-phase phenomenon in which a gas bubble is forced to have astrong spherically converging inertial collapse. The sudden pressure and density rise within the bubble contentis sufficiently rapid to almost adiabatically heat the gas until a hot plasma is formed and a very short durationlight pulse is emitted. In the present research we report several experimental and numerical results on theinfluence of static pressure (P0) over the main parameters in SBSL, using a sulphuric acid aqueous solution(SA) with low concentrations of argon gas dissolved. Measurements of the temporal evolution of the bubbleradius were compared with simulations provided by a state of the art numerical code that models the radialdynamics of the bubbles. The results showed that an increase on the static pressure of the system shifts theBjerknes instability threshold, allowing the bubble to access higher acoustic pressures (PAc). Furthermore, adecrease in the measured ambient radius R0 and the calculated relative gas concentration c∞/c0 were observed.A notorious increment in the maximum temperature during the bubble collapse was observed for high staticpressures above the atmospheric. Finally, we analyzed the stability regions of the R0- PAc parameter space forP0 above the measured via numerical predictions, identifying the shape instabilities as the main limiting agentto obtain further energy concentration in SA systems at high static pressures.