A rising bubble in a polymer solution

Málaga, Carlos; Rallison, J. M.

doi:10.1016/j.jnnfm.2006.07.012

Cited by 45 publications

(40 citation statements)

References 30 publications

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“…It is also noteworthy that the observed bubble shapes inside a vertical pipe were different from [16] exhibiting a cusped tail, resembling much the inverted teardrop shapes often found inside a viscoelastic medium [16,19,20]. Similar bubble shapes have been found in the experimental studies by Sikorski et al [21] and Mougin et al [22], using Carbopol solutions of different concentrations.…”

Section: Introductionsupporting

confidence: 79%

Bubble rise dynamics in a viscoplastic material

Tripathi

Sahu

Karapetsas

et al. 2015

Journal of Non-Newtonian Fluid Mechanics

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The axisymmetric dynamics of a bubble rising in a Bingham fluid under the action of buoyancy is studied. The Volume-of-Fluid (VOF) method is used to solve the equations of mass and momentum conservation, coupled to an equation for the volume fraction of the Bingham fluid. A regularised constitutive model is used for the description of the viscoplastic behaviour of the material. The numerical results demonstrate that the rise dynamics are complex for large yield stresses, and for weak surface tension. Under these conditions, for which the bubble is highly deformable, the rise is unsteady and is punctuated by periods of rapid acceleration which separate stages of quasi-steady motion. During the acceleration periods, the bubble aspect ratio exhibits oscillations about unity, whose amplitude and wavelength increase with increasing yield stress and decreasing surface tension. These oscillations are accompanied by the alternating formation and destruction of unyielded

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Section: Introductionsupporting

confidence: 79%

Bubble rise dynamics in a viscoplastic material

Tripathi

Sahu

Karapetsas

et al. 2015

Journal of Non-Newtonian Fluid Mechanics

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“…Cusped bubbles have been observed in several types of non-Newtonian fluids, including purely elastic fluids and shearthinning viscoelastic fluids [3,12,22,32,33]. It has been suggested on the basis of numerical studies that the cusp in viscoelastic fluids arises due to a strong uniaxial extensional flow or a negative wake behind the rising bubble, resulting from the stretching of polymer molecules [23][24][25][26]. The recent numerical work by Tsamopoulos et al [16], which did not include elasticity, predicts an elongation of the bubbles in the z-direction as y increases but not the strongly tapered tails observed here and in Ref.…”

Section: Discussionmentioning

confidence: 99%

“…Bubbles with tapered tails were observed in yield-stress fluids in the experiments of Ref. [6], and cusped tails have also been observed in bubbles rising through viscoelastic fluids with no yield stress [22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 86%

Motion and shape of bubbles rising through a yield-stress fluid

Sikorski

Tabuteau

Bruyn

2009

Journal of Non-Newtonian Fluid Mechanics

112

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a b s t r a c tWe study the velocity and shape of air bubbles rising through a transparent yield-stress fluid. The bubbles are small enough compared to the experimental vessel that effects of walls are weak. We find that the terminal rise velocity of the bubbles increases approximately linearly with bubble radius over the range of volumes accessible in our experiments. We observe bubble motion only when the bubbles are larger than a certain critical radius. In terms of a dimensionless yield parameter Y, the ratio between the force due to the yield stress and the buoyant force, we observe bubble motion only for Y 0.50 ± 0.04. The bubbles are non-spherical, having the shape of an inverted teardrop with a rounded head and a cusp-like tail. The cusps may be an indication that elasticity plays a significant role in this system. By fitting the cross-sectional radius of the bubble as a function of the axial coordinate to an empirical function, we study the dependence of the bubble shape on volume and the yield stress of the material.

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“…19) Interestingly, the validity of spherical symmetry can also be violated for small bubbles at very high Reynolds numbers (due to shape instability) and/or when a bubble becomes too close to a solid wall. 20) None of these mechanisms are operating in this work because we are assuming that the bubble size is always of the order of one micron.…”

Section: Discussionmentioning

confidence: 99%

The Rise of Second Harmonics in Forced Oscillation of Gas Bubbles in Thixotropic Fluids

Ahmadpour

Amini-Kafiabad

Samadi

et al. 2011

J. Soc. Rheol., Jpn

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In the present work, nonlinear acoustic oscillation of a single spherical gas bubble immersed in an unbounded thixotropic fluid is studied numerically. Using Moore's structural model as the constitutive equation of the liquid surrounding the bubble, the general Rayleigh-Plesset integro-differential equation, which governs bubble dynamics, is solved numerically using the Gauss-Laguerre Quadrature (GLQ) method. It is shown that at sufficiently high pressure amplitudes, typical of medical ultrasound applications, a second harmonics may be observed in the bubble's response.

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A rising bubble in a polymer solution

Cited by 45 publications

References 30 publications

Bubble rise dynamics in a viscoplastic material

Bubble rise dynamics in a viscoplastic material

Motion and shape of bubbles rising through a yield-stress fluid

The Rise of Second Harmonics in Forced Oscillation of Gas Bubbles in Thixotropic Fluids

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