Effects of dynamic interfacial properties on drop deformation and orientation in shear and extensional flow fields

Flumerfelt, Raymond W.

doi:10.1016/0021-9797(80)90377-x

Cited by 82 publications

(78 citation statements)

References 13 publications

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“…For Bq 1, it disappears. At small capillary number Ca = 0.1 characterized by small deformations, there is a good agreement with the theory of Flumerfelt (1980) on all the range of viscosity contrast and Boussinesq number. The agreement is also excellent for viscosity contrast larger than 100 whatever Ca and Bq.…”

Section: Surface Viscosity Bq = Bq S = Bq Dsupporting

confidence: 66%

“…Even at the two higher capillary numbers, agreement is surprisingly consistent. In the limit of large Boussinesq number, Bq 30, the inclination and the Taylor parameter are in excellent agreement with Flumerfelt (1980) whatever the capillary number. Only as Bq → 0 does divergence emerge for D, reflecting the known disparity for clean droplets.…”

Section: Surface Viscosity Bq = Bq S = Bq Dsupporting

confidence: 62%

“…We return to the case Bq s = Bq d . With Ca = 0.1, the smallest deformations occur and the agreement between the present method and Flumerfelt (1980) for D is excellent except at zero Bq. Even at the two higher capillary numbers, agreement is surprisingly consistent.…”

Section: Surface Viscosity Bq = Bq S = Bq Dmentioning

confidence: 83%

“…Accordingly, we compare in figure 10 the steady-state behaviour of droplets with surface viscosity Bq to the predictions from the small deformation analysis of Flumerfelt (1980) which is currently the only one taking into account the dilational and shear interface viscosities. Unless they are very heavily deformed, the steady-state shapes for droplets with surface viscosity are approximately ellipsoidal and, therefore, are well described by the Taylor deformation parameter D.…”

Section: Surface Viscosity Bq = Bq S = Bq Dmentioning

confidence: 99%

“…The principal result is from Flumerfelt (1980), who extended the small deformation analysis of Cox (1969) for the deformation and inclination angle of droplets in linear flows to incorporate the additional effects of surface viscosity and small gradients in surface tension. Flumerfelt's results suggested that shear and dilational surface viscosity had rather distinct impacts on droplet deformation.…”

Section: Introductionmentioning

confidence: 99%

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Influence of surface viscosity on droplets in shear flow

et al. 2016

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The behaviour of a single droplet in an immiscible external fluid, submitted to shear flow is investigated using numerical simulations. The surface of the droplet is modelled by a Boussinesq-Scriven constitutive law involving the interfacial viscosities and a constant surface tension. A numerical method using Loop subdivision surfaces to represent droplet interface is introduced. This method couples boundary element method for fluid flows and finite element method to take into account the stresses due to the surface dilational and shear viscosities and surface tension. Validation of the numerical scheme with respect to previous analytic and computational work is provided, with particular attention to the viscosity contrast and the shear and dilational viscosities characterized both by a Boussinesq number B q . Then, influence of equal surface viscosities on steady-state characteristics of a droplet in shear flow are studied, considering both small and large deformations and for a large range of bulk viscosity contrast. We find that small deformation analysis is surprisingly predictive at moderate and high surface viscosities. Equal surface viscosities decrease the Taylor deformation parameter and tank-treading angle and also strongly modify the dynamics of the droplet: when the Boussinesq number (surface viscosity) is large relative to the capillary number (surface tension), the droplet displays damped oscillations prior to steady-state tank-treading, reminiscent from the behaviour at large viscosity contrast. In the limit of infinite capillary number Ca, such oscillations are permanent. The influence of surface viscosities on breakup is also investigated, and results show that the critical capillary number is increased. A diagram (B q ; Ca) of breakup is established with the same inner and outer bulk viscosities. Additionally, the separate roles of shear and dilational surface viscosity are also elucidated, extending results from small deformation analysis. Indeed, shear (dilational) surface viscosity increases (decreases) the stability of drops to breakup under shear flow. The steady-state deformation (Taylor parameter) varies nonlinearly with each Boussinesq number or a linear combination of both Boussinesq numbers. Finally, the study shows that for certain combinations of shear and dilational viscosities, drop deformation for a given capillary number is the same as in the case of a clean surface while the inclination angle varies.

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Section: Surface Viscosity Bq = Bq S = Bq Dsupporting

confidence: 66%

Section: Surface Viscosity Bq = Bq S = Bq Dsupporting

confidence: 62%

Section: Surface Viscosity Bq = Bq S = Bq Dmentioning

confidence: 83%

Section: Surface Viscosity Bq = Bq S = Bq Dmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of surface viscosity on droplets in shear flow

et al. 2016

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A finite difference method with subsampling for immersed boundary simulations of the capsule dynamics with viscoelastic membranes

Zhang

2019

Numer Methods Biomed Eng

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Emulsion Drops with Complex Interfaces: Globular Versus Flexible Proteins

Erni

Windhab

Fischer

2011

Macro Materials & Eng

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This study focuses on the flow behavior of emulsion drops with complex interfaces. The experimental approach includes three different length scales: (i) interfacial rheology is discussed for adsorbed proteins with different molecular structure (compact and globular for beta‐lactoglobulin versus flexible and random coil for beta‐casein); (ii) the flow of single drops with macromolecular adsorption layers is studied using optical flow cells; (iii) dilute emulsions are investigated using rheology and rheo‐small angle light scattering (rheo‐SALS). Different hydrodynamic models for drops with and without interfacial viscoelasticity are assessed. For the case of rigid interfacial layers, a comparison with capsule suspension models suggests that drops stabilized by adsorbed particles or globular proteins behave like “soft capsules” surrounded by a jammed shell. Their behavior on the single drop level is similar to the mechanics of red blood cells or vesicles. magnified image

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Effects of dynamic interfacial properties on drop deformation and orientation in shear and extensional flow fields

Cited by 82 publications

References 13 publications

Influence of surface viscosity on droplets in shear flow

Influence of surface viscosity on droplets in shear flow

A finite difference method with subsampling for immersed boundary simulations of the capsule dynamics with viscoelastic membranes

Emulsion Drops with Complex Interfaces: Globular Versus Flexible Proteins

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