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

Sikorski, Darek; Tabuteau, Hervé; Bruyn, John R. de

doi:10.1016/j.jnnfm.2008.11.011

Cited by 109 publications

(90 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…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. The latter authors also studied the significant role of internal trapped stresses within a Carbopol gel on the trajectory and shape of the bubbles; their findings were in agreement with an earlier study presented by Piau [23].…”

Section: Introductionsupporting

confidence: 87%

“…It was shown that the critical Bingham number, Bn, does not depend on the Archimedes number in accordance with Tsamopoulos et al [4], but depends non-monotonically on surface tension. We should note that in both studies the shape of the bubble near critical conditions could not reproduce the inverted teardrop shapes seen in experiments [18,21,22] and raised questions whether this is due to elasticity, thixotropy or wall effects. Besides the steady solutions it is also interesting to investigate the bubble dynamics through time-dependent simulations.…”

Section: Introductionmentioning

confidence: 85%

See 1 more Smart Citation

Bubble rise dynamics in a viscoplastic material

Tripathi

Sahu

Karapetsas

et al. 2015

Journal of Non-Newtonian Fluid Mechanics

View full text Add to dashboard Cite

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

show abstract

Section: Introductionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 85%

Bubble rise dynamics in a viscoplastic material

Tripathi

Sahu

Karapetsas

et al. 2015

Journal of Non-Newtonian Fluid Mechanics

View full text Add to dashboard Cite

show abstract

“…Note that the equivalent critical value of the yield parameter for bubbles is 0.53 (Sikorski et al, 2009). The same range of yield stresses implies that bubbles must have minimum diameters of 2.1 cm to 4.4 cm in order to rise through the mud.…”

Section: Size Of Particles Supported By the Yield Stressmentioning

confidence: 97%

Large historical eruptions at subaerial mud volcanoes, Italy

Manga

Bonini

2012

Nat. Hazards Earth Syst. Sci.

View full text Add to dashboard Cite

Abstract. Active mud volcanoes in the northern Apennines, Italy, currently have gentle eruptions. There are, however, historical accounts of violent eruptions and outbursts. Evidence for large past eruptions is also recorded by large decimeter rock clasts preserved in erupted mud. We measured the rheological properties of mud currently being erupted in order to evaluate the conditions needed to transport such large clasts to the surface. The mud is wellcharacterized by the Herschel-Bulkley model, with yield stresses between 4 and 8 Pa. Yield stresses of this magnitude can support the weight of particles with diameters up to several mm. At present, particles larger than this size are not being carried to the surface. The transport of larger clasts to the surface requires ascent speeds greater than their settling speed in the mud. We use a model for the settling of particles and rheological parameters from laboratory measurements to show that the eruption of large clasts requires ascent velocities > 1 m s −1 , at least three orders of magnitude greater than during the present, comparatively quiescent, activity. After regional earthquakes on 20 May and 29 May 2012, discharge also increased at locations where the stress changes produced by the earthquakes would have unclamped feeder dikes below the mud volcanoes. The magnitude of increased discharge, however, is less than that inferred from the large clasts. Both historical accounts and erupted deposits are consistent in recording episodic large eruptions.

show abstract

“…This issue was discussed, at first, by Besagni and Inzoli and, later, by Besagni et al ) who analyzed bubble sizes and shapes in air-water bubble column and proposed correlations for the aspect ratio valid for dense bubbly flows. Despite the fact that some studies investigated the shapes of single rising bubbles in viscous media (Aoyama et al, 2016;Dimakopoulos et al, 2013;Fraggedakis et al, 2016;Gumulya et al, 2016;Sikorski et al, 2009;Tsamopoulos et al, 2008), the relations between the bubble size and shapes in dense bubbly flows with viscous media remains unanswered. In addition, the available databases of the bubble aspect ratios in viscous liquids are still insufficient, as observed by Aoyama et al (2016), and additional data are needed to better establish and extend the range of validity of the existing correlations to estimate the bubble shapes.…”

Section: Influence Of Viscosity On the Bubble Size Distributions And mentioning

confidence: 99%

The dual effect of viscosity on bubble column hydrodynamics

Besagni

Inzoli

Guido

et al. 2017

Chemical Engineering Science

110

View full text Add to dashboard Cite

A B S T R A C TSome authors, in the last decades, have observed the dual effect of viscosity on gas holdup and flow regime transition in small-diameter and small-scale bubble columns. This work concerns the experimental investigation of the dual effect of viscosity on gas holdup and flow regime transition as well as bubble size distributions in a large-diameter and large-scale bubble column. The bubble column is 5.3 m in height, has an inner diameter of 0.24 m, and can be operated with gas superficial velocities in the range of 0.004-0.20 m/s. Air was used as the dispersed phase, and various water-monoethylene glycol solutions were employed as the liquid phase. The water-monoethylene glycol solutions that were tested correspond to a viscosity between 0.9 mPa s and 7.97 mPa s, a density between 997.086 kg/m 3 and 1094.801 kg/m 3 , a surface tension between 0.0715 N/m and 0.0502 N/m, and log 10 (Mo) between −10.77 and −6.55 (where Mo is the Morton number). Gas holdup measurements were used to investigate the global fluid dynamics and the flow regime transition between the homogeneous flow regime and the transition flow regime. An image analysis method was used to investigate the bubble size distributions and shapes for different gas superficial velocities, for different solutions of watermonoethylene glycol. In addition, based on the experimental data from the image analysis, a correlation between the bubble equivalent diameter and the bubble aspect ratio was proposed. The dual effect of viscosity, previously verified in smaller bubble columns, was confirmed not only with respect to the gas holdup and flow regime transition, but also for the bubble size distributions. Low viscosities stabilize the homogeneous flow regime and increase the gas holdup, and are characterized by a larger number of small bubbles. Conversely, higher viscosities destabilize the homogeneous flow regime and decrease the gas holdup, and the bubble size distribution moves toward large bubbles. The experimental results suggest that the stabilization/destabilization of the homogeneous regime is related to the changes in the bubble size distributions and a simple approach, based on the lift force, was proposed to explain this relationship. Finally, the experimental results were compared to the dual effect of organic compounds and inorganic compounds: future studies should propose a comprehensive theory to explain all the dual effects observed.

show abstract

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

Cited by 109 publications

References 29 publications

Bubble rise dynamics in a viscoplastic material

Bubble rise dynamics in a viscoplastic material

Large historical eruptions at subaerial mud volcanoes, Italy

The dual effect of viscosity on bubble column hydrodynamics

Contact Info

Product

Resources

About