SECTION: Mechanics and engineering. Energy
SCIENTIFIC ORGANIZATION:
Bashkir State University
REPORT FORM:
«Poster report»
AUTHOR(S)
OF THE REPORT:
S.P. Sametov, Y.A. Itkulova, N.A. Gumerov, C.-D. Ohl, and I.S. Akhatov
SPEAKER:
Sametov Sergey
REPORT TITLE:
Numerical and Experimental Study of Non-spherical Bubble Dynamics.
TALKING POINTS:

Some interesting theoretical and practical issues arising from peculiar behavior of non-spherical bubbles, like the phenomena of chaotic self-propulsion and so-called “dancing bubble”, and energy transfer between surface and volume modes are important for ultrasonic cleaning of solid surfaces. The aim of the present study is shape and volume oscillations of a single bubble. Problem solution includes both numerical and experimental approaches. For the first one the boundary element method (BEM) for potential flow which offers a low computational cost and provides an accurate representation of bubble surface is employed. To accelerate computations and increase problem size the fast multipole method (FMM) and graphics processors (GPUs) are used. The second one is based on high speed recording and using of contemporary experimental equipment. First, the dynamics of exited high order surface modes of bubble at free and forced bubble oscillations, bubble self-propulsion, and transfer of energy between surface and volume modes in unbounded liquid are studied numerically. Second, in the experiment the behavior of surface attached bubble in an acoustic field is observed and physical parameters are obtained. Using the present data BEM calculations are implemented showing a good agreement with experimental data. The results show the excitation of bubble surface modes after several volume oscillations. It can be explained by energy transfer between shape and volume modes of a bubble. Moreover in experiment it is observed that the shape oscillations can lead to the detaching of a bubble from solid wall and further bubble propulsion along a substrate. This effect may be essential for understanding of surface cleaning process. As a future work the BEM code is expanded in order to simulatetotal physical process observed experimentally, including bubble detachment and moving contact line. This study is supported by Grant of Ministry of Education and Science of the Russian Federation (11.G34.31.0040), Christian Doppler Research Association (Austria), Goettingen University (Germany), and Fantalgo, LLC (Maryland, USA).