Enhancing acoustic cavitation using artificial crevice bubbles

Aaldert Zijlstra; David Fernandez Rivas; Han J G E Gardeniers; Michel Versluis; Detlef Lohse

doi:10.1016/j.ultras.2014.10.002

Enhancing acoustic cavitation using artificial crevice bubbles

Ultrasonics. 2015 Feb:56:512-23. doi: 10.1016/j.ultras.2014.10.002. Epub 2014 Oct 18.

Authors

Aaldert Zijlstra¹, David Fernandez Rivas², Han J G E Gardeniers³, Michel Versluis¹, Detlef Lohse¹

Affiliations

¹ Physics of Fluids Group, MESA+Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
² Mesoscale Chemical Systems Group, MESA+Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands. Electronic address: d.fernandezrivas@utwente.nl.
³ Mesoscale Chemical Systems Group, MESA+Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.

PMID: 25455191
DOI: 10.1016/j.ultras.2014.10.002

Abstract

We study the response of pre-defined cavitation nuclei driven continuously in the kHz regime (80, 100 and 200 kHz). The nuclei consist of stabilized gaspockets in cylindrical pits of 30 μm diameter etched in silicon or glass substrates. It is found that above an acoustic pressure threshold the dynamics of the liquid-gas meniscus switches from a stable drum-like vibration to expansion and deformation, frequently resulting in detachment of microbubbles. Just above this threshold small bubbles are continuously and intermittently ejected. At elevated input powers bubble detachment becomes more frequent and cavitation bubble clouds are formed and remain in the vicinity of the pit bubble. Surprisingly, the resulting loss of gas does not lead to deactivation of the pit which can be explained by a rectified gas diffusion process.

Keywords: Bubble; Cavitation; High-speed imaging; Nucleation; Ultrasound.