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- Title
Multiscale Numerical Simulation of Bubble Cloud Formation in Focused Ultrasound.
- Authors
NAKAO Mebuki; YAMAUCHI Hideki; OGASAWARA Toshiyuki; TAKAHIRA Hiroyuki
- Abstract
This study deals with a numerical simulation of the growth of bubble nuclei and the corresponding bubble cloud formation in a pressure field given by high intensity focused ultrasound (HIFU) backscattered from a laser-induced bubble interface. In the present paper, using a multiscale numerical method (Tamura et al., Japanese J. Multiphase Flow, 2022) in which the ghost fluid method is coupled with bubble dynamics, the growth of the bubble cloud which consists of multiple bubble layers is simulated continuously as observed in the experiments. It is shown that the distance between the first cavitation inception point and a laser-induced bubble interface is about 0.27λ, where λ, is the wavelength of HIFU; the distance between bubble layers in the cloud is also about 0.35λ: these distances in the simulation are in good agreement with the experiments. The influence of the configuration of bubble nuclei on the final form of a cone-shaped bubble cloud is investigated. It is also shown that the shape of each bubble layer, which depends on the initial configuration of bubble nuclei, affects the final formation of bubble clouds. This is because that the negative pressure due to the backscattering of HIFU is dependent on the shape of each bubble layer. The results also show that the averaged final shape of bubble clouds quantitively matches the results as observed in the experiment by Horiba et al. (J. Acoust. Soc. Am., 2020).
- Subjects
NUCLEAR density; MICROBUBBLE diagnosis; MULTIPHASE flow; COMPUTER simulation; HIGH-intensity focused ultrasound; BUBBLE dynamics; CAVITATION
- Publication
Japanese Journal of Multiphase Flow, 2023, Vol 37, Issue 1, p120
- ISSN
0914-2843
- Publication type
Article