Доступ предоставлен для: Guest
Портал Begell Электронная Бибилиотека e-Книги Журналы Справочники и Сборники статей Коллекции
Multiphase Science and Technology
SJR: 0.124 SNIP: 0.222 CiteScore™: 0.26

ISSN Печать: 0276-1459
ISSN Онлайн: 1943-6181

Выпуски:
Том 32, 2020 Том 31, 2019 Том 30, 2018 Том 29, 2017 Том 28, 2016 Том 27, 2015 Том 26, 2014 Том 25, 2013 Том 24, 2012 Том 23, 2011 Том 22, 2010 Том 21, 2009 Том 20, 2008 Том 19, 2007 Том 18, 2006 Том 17, 2005 Том 16, 2004 Том 15, 2003 Том 14, 2002 Том 13, 2001 Том 12, 2000 Том 11, 1999 Том 10, 1998 Том 9, 1997 Том 8, 1994 Том 7, 1993 Том 6, 1992 Том 5, 1990 Том 4, 1989 Том 3, 1987 Том 2, 1986 Том 1, 1982

Multiphase Science and Technology

DOI: 10.1615/MultScienTechn.v17.i4.30
pages 343-371

STRUCTURE FORMATION IN ACOUSTIC CAVITATION

S. Konovalova
Institute of Mechanics, Ufa Branch of the Russian Academy of Sciences, Ufa, Russia
I. S. Akhatov
Dept. of Mechanical Engineering & Applied Mechanics, North Dakota State University, Fargo, ND, USA

Краткое описание

Bubble clouds forming in a liquid subject to a strong acoustic excitation, that is called acoustic cavitation, show a complicated slowly varying filamentary structure. This bubbly mixture represents a multiphase system whose physical origin is still not completely understood. Basic physical interactions in such bubbly liquid comprised of nonlinear bubble dynamics, Bjerknes and drag forces, interaction between bubbles, wave dynamics, etc. In the introduction section a brief overview of various theoretical approaches to this phenomenon is presented. The paper gives a systematic representation of particle model for describing the structure formation process in a bubbly liquid. In the framework of the particle model all bubbles are treated as interacting objects that move in the liquid.
A mathematical model for coupled, radial and translational, motion of a small spherical cavitation bubbles driven below its resonance frequency in a strong acoustic field (Pa > 1 bar, f = 20 kHz) is presented. Numerical analysis of the dynamics of a single bubble shows that, within the limits of harmonic resonances of the system, period-doubling bifurcations cascades with transitions to chaos and back to regular dynamics take place. A possible mechanism for the erratic dancing mode of bubble motion is proposed. Besides erratic dancing, the low-frequency quasi-periodic translational motion (periodic dancing) mode is observed at certain values of bubble radii. For a pair of interacting bubbles various dynamic modes are obtained: simple attraction, periodic motion and asymptotic motion, when the bubbles tend to take steady positions on a vertical line crossing the pressure antinode. In the last two cases bubbles do not coalesce, but are bound into couples, which cannot be predicted by a classic linear theory. This is explained by so-called giant response of small bubbles. Thus, the nonlinear effects can result in self-organization of bubble clouds. Structure formation processes in bubble clouds are simulated numerically. The characteristic bubble sizes in the structures, as well as dimension and shape of the structures are in qualitative agreement with the experimental observations.