The Temperature of Cavitation

TLDR

Ultrasonic irradiation of liquids induces acoustic cavitation, where bubble collapse creates transient hot spots that drive high‑energy chemistry and light emission, yet measuring the temperatures reached remains experimentally challenging. The study proposes using sonoluminescence as a spectroscopic probe to determine cavitation temperatures. The authors analyzed sonoluminescence spectra obtained from silicone oil to extract temperature information. Synthetic spectral fitting of the C₂ Swan band emission revealed an effective cavitation temperature of 5 075 ± 156 K.

Abstract

Ultrasonic irradiation of liquids causes acoustic cavitation: the formation, growth, and implosive collapse of bubbles. Bubble collapse during cavitation generates transient hot spots responsible for high-energy chemistry and emission of light. Determination of the temperatures reached in a cavitating bubble has remained a difficult experimental problem. As a spectroscopic probe of the cavitation event, sonoluminescence provides a solution. Sonoluminescence spectra from silicone oil were reported and analyzed. The observed emission came from excited state C 2 (Swan band transitions, d 3 II g — a 3 II u ), which has been modeled with synthetic spectra as a function of rotational and vibrational temperatures. From comparison of synthetic to observed spectra, the effective cavitation temperature was found to be 5075 ± 156 K.