Cavitation-induced shock wave behaviour in different liquids

• Published in: Ultrasonics sonochemistry Vol. 94; p. 106328
• Main Authors: Khavari, Mohammad, Priyadarshi, Abhinav, Morton, Justin, Porfyrakis, Kyriakos, Pericleous, Koulis, Eskin, Dmitry, Tzanakis, Iakovos
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.03.2023; Elsevier
• Subjects: Bubble cloud; Original; Shock wave; Ultrasonic cavitation; Ultrasonic cavitation; Bubble cloud; Shock wave
• ISSN: 1350-4177; 1873-2828
• DOI: 10.1016/j.ultsonch.2023.106328

•Spatio-temporal evolution of shock wave (SW) dynamics studied in different liquids.•Shifting of SW frequency peak attributed to changes in speed of sound (V).•Cavitation zone and shielding increase with input power in all liquids but glycerol.•Ethanol-water mixture deemed to be suitable for synthesis of nanomaterials. This paper follows our earlier work where a strong high frequency pressure peak has been observed as a consequence of the formation of shock waves due to the collapse of cavitation bubbles in water, excited by an ultrasonic source at 24 kHz. We study here the effects of liquid physical properties on the shock wave characteristics by replacing water as the medium successively with ethanol, glycerol and finally a 1:1 ethanol–water solution. The pressure frequency spectra obtained in our experiments (from more than 1.5 million cavitation collapsing events) show that the expected prominent shockwave pressure peak was barely detected for ethanol and glycerol, particularly at low input powers, but was consistently observed for the 1:1 ethanol–water solution as well as in water, with a slight shift in peak frequency for the solution. We also report two distinct features of shock waves in raising the frequency peak at MHz (inherent) and contributing to the raising of sub-harmonics (periodic). Empirically constructed acoustic pressure maps revealed significantly higher overall pressure amplitudes for the ethanol–water solution than for other liquids. Furthermore, a qualitative analysis revealed that mist-like patterns are developed in ethanol–water solution leading to higher pressures.