Sarah Cleve (Twente) - Microstreaming around a nonspherically oscillating microbubble
Microbubbles used in medical ultrasound applications are known to induce microstreaming, a relatively slow mean flow with respect to the fast bubble oscillations. While microstreaming and its associated shear stresses are commonly agreed to play a role in the permeabilization of cell membranes, a detailed understanding of the induced flows is however missing. To acquire basic physical knowledge, my experimental work focused on the characterization of microstreaming induced around an air bubble in water, more precisely around a single acoustically trapped and excited, nonspherically oscillating bubble. For this, I recorded microstreaming and correlated it to the bubble dynamics. The surprisingly large number of obtained pattern types can be classified to gather understanding of the physical mechanisms involved. Bubble size and mode number play an important role in the definition of the pattern types, but my analysis also revealed further parameters to take into account. In order to confirm the experimental findings, an analytical model has been developed and shows good agreement with the experimental results.
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- jeudi 4 mars 2021 11:30