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Physical forces exerted by microbubbles on a surface in a traveling wave field.

Research paper by S S Brems, M M Hauptmann, E E Camerotto, P W PW Mertens, M M Heyns, H H Struyf, S S De Gendt

Indexed on: 05 Oct '13Published on: 05 Oct '13Published in: Ultrasonics



Abstract

The effect of a wave with a varying traveling component on the bubble activity as well as the physical force generated by microbubbles on a surface has been studied. The acoustic emission from a collection of bubbles is measured in a 928 kHz sound field. Particle removal tests on a surface, which actually measures the applied physical force by the bubbles on that surface, indicate a very strong dependence on the angle of incidence. In other words, when the traveling wave component is maximized, the average physical force applied by microbubbles reaches a maximum. Almost complete particle removal for 78 nm silica particles was obtained for a traveling wave, while particle removal efficiency was reduced to only a few percent when a standing wave was applied. This increase in particle removal for a traveling wave is probably caused by a decrease in bubble trapping at nodes and antinodes in a standing wave field.