Oscillations of small bubbles and medium yielding in elastoviscoplastic fluids
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Published version
Author(s)
Type
Journal Article
Abstract
We investigate the radial oscillations of small gas bubbles trapped in yield-stress fluids and driven by an acoustic pressure field. We model the rheological behavior of the yield-stress fluid using the recently developed elastoviscoplastic constitutive equation that takes into account the elastic and viscoplastic deformations of the material [Saramito, J. Non-Newton. Fluid Mech. 158, 154 (2009)]. Assuming that the bubble remains spherical during the pressure driving, we reduce the problem to a set of ordinary differential equations and an integrodifferential equation, which we solve numerically for the case of two yield-stress fluids, i.e., a soft Carbopol gel and a stiffer kaolin suspension. We find that depending on the amplitude and frequency of the pressure field, the radial oscillations of the bubble produce elastic stresses that may or may not suffice to yield the surrounding material. We evaluate the critical amplitude of the acoustic pressure required to achieve yielding and we find a good agreement between numerical simulations and an analytical formula derived under the assumption of linear deformations. Finally, we examine the bubble oscillation amplitude for a very wide range of applied pressures both below and above the critical value to assess the impact of yielding on the bubble dynamics. This analysis could be used to identify a signature of yielding in experiments where the radial dynamics of a bubble is measured. More generally, these results can be used to rationalize the optimal conditions for pressure-induced bubble release from yield-stress fluids, which is relevant to various biomedical and industrial applications, including the oil industry and food processing.
Date Issued
2019-07-01
Date Acceptance
2019-07-01
Citation
Physical Review Fluids, 2019, 4 (7), pp.073301-1-073301-21
ISSN
2469-990X
Publisher
American Physical Society
Start Page
073301-1
End Page
073301-21
Journal / Book Title
Physical Review Fluids
Volume
4
Issue
7
Copyright Statement
©2019 American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000473312300001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Physical Sciences
Physics, Fluids & Plasmas
Physics
AUGMENTED LAGRANGIAN METHOD
GAS-BUBBLES
VISCOELASTIC FLUIDS
STRESS ANALYSIS
DYNAMICS
SOFT
MOTION
FLOWS
CAVITATION
ULTRASOUND
Publication Status
Published
Article Number
ARTN 073301
Date Publish Online
2019-07-01