Open AccessJournal Article
Hindered and Enhanced Coalescence of Drops in Stokes Flows
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TLDR
In this paper, it is shown that hydrodynamic stresses in the near contact region that are associated with the outer flow can qualitatively affect the drainage of the thin fluid film separating the drops.Abstract:
We analyze axisymmetric near-contact motion of two drops under the action of an external force or imposed flow. It is shown that hydrodynamic stresses in the near-contact region that are associated with the outer (drop-scale) flow can qualitatively affect the drainage of the thin fluid film separating the drops. If this far-field stress acts radially inward, film drainage is arrested at long times; exponential film drainage occurs if this stress acts outward. An asymptotic analysis of the stationary long-time film profile is presented for small-deformation conditions, and the critical strength of van der Waals attraction for film rupture is calculated. The effect of an insoluble surfactant is also considered. Hindered and enhanced drop coalescence are not predicted by the current theories, because the influence of the outer flow on film drainage is ignored.read more
Citations
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Droplet collisions in turbulence
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The Creeping Motion and Deformation of Drops in Solid Constrictions
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References
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Journal ArticleDOI
Film drainage and coalescence between deformable drops and bubbles
TL;DR: In this article, the authors compare the results obtained from many different experimental approaches with either theory and conclude that their predictions of the fate of the draining film are quite different. But with the recent availability of accurate experimental studies concerning dynamic interaction between drops and bubbles that use very different, but complementary approaches, it is timely to conduct a critical review to compare such results with long-accepted paradigms of film stability and coalescence.
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Diffuse-interface simulations of drop coalescence and retraction in viscoelastic fluids
TL;DR: In this article, the authors used a twodimensional implementation of the method to simulate drop coalescence after head-on collision and drop retraction from an elongated initial shape in a quiescent matrix.
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Coalescence of two equal-sized deformable drops in an axisymmetric flow
TL;DR: In this article, the coalescence of two equal-sized deformable drops in an axisymmetric flow is studied, using a boundary-integral method, and an adaptive mesh refinement method is used to resolve the local small-scale dynamics in the gap and to retain a reasonable speed of computation.
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Droplet coalescence: drainage, film rupture and neck growth in ultralow interfacial tension systems
TL;DR: In this article, the authors studied the coalescence of a drop with its bulk phase in fluid-fluid demixing colloid-polymer mixtures, showing that the interfacial tension is between 105 to 107 times smaller than in the molecular case.
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Separation-driven coalescence of droplets: an analytical criterion for the approach to contact
TL;DR: In this article, a two-dimensional model is proposed to determine the deformation of a droplet at the time of contact, where the deformed droplet is estimated by a non-dimensional parameter A = 4CμR2α1/2/πγ[h0(0)]3/2, where μ is the viscosity of the continuous phase; γ is the interfacial tension; and C depends on the visco-temperature ratio between the droplets and the continuous phases.