scholarly journals Viscoelastic drop deformation in simple shear flow investigated by the front tracking method

2007 ◽  
Author(s):  
C. Chung ◽  
M. A. Hulsen ◽  
K. H. Ahn ◽  
S. J. Lee
Keyword(s):  
Shear Flow ◽  
Simple Shear ◽  
Front Tracking ◽  
Drop Deformation ◽  
Simple Shear Flow ◽  
Tracking Method ◽  
Front Tracking Method

Deformation of spherical compound capsules in simple shear flow

2015 ◽  
Vol 775 ◽  
pp. 77-104 ◽  
Author(s):  
Zheng Yuan Luo ◽  
Long He ◽  
Bo Feng Bai
Keyword(s):  
Shear Flow ◽  
Numerical Simulations ◽  
Simple Shear ◽  
Three Dimensional ◽  
Volume Ratio ◽  
Constitutive Law ◽  
Simple Shear Flow ◽  
Outer Membranes ◽  
Front Tracking Method ◽  
Outer Capsule

The deformation of a compound capsule (an elastic capsule with a smaller capsule inside) in simple shear flow is studied by using three-dimensional numerical simulations based on a front tracking method. The inner and outer capsules are concentric and initially spherical. Skalaket al.’s constitutive law is employed for the mechanics of both the inner and outer membranes. Our results concerning the deformation of homogeneous capsules (i.e. capsules without the inner capsules) are quantitatively in agreement with the predictions of previous numerical simulations and perturbation theories. Compared to homogeneous capsules, compound capsules exhibit smaller deformation. The deformations of both the inner and outer capsules are significantly affected by the capillary numbers of the inner and outer membranes and the volume ratio of the inner to the outer capsule. When the inner capsule is small, it presents smaller deformation than the outer capsule. However, when the inner capsule is sufficiently large, it can present larger deformation than the outer capsule, even if the inner membrane has much lower capillary number than the outer membrane. The underlying mechanisms are discussed: (i) the inner capsule is deformed by rotational flow with lower rate of strain rather than by simple shear flow that deforms the outer capsule, and thus the inner capsule exhibits smaller deformation; and (ii) when the inner and outer membranes are sufficiently close (i.e. the inner capsule is sufficiently large), the hydrodynamic interaction between the two membranes becomes significant, which is found to inhibit the deformation of the outer capsule but to promote the deformation of the inner capsule.

scholarly journals Collision Modes of Two Eccentric Compound Droplets

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 602
Author(s):  
Khanh P. Nguyen ◽  
Truong V. Vu
Keyword(s):  
Shear Flow ◽  
Simple Shear ◽  
Front Tracking ◽  
The Other ◽  
Simple Shear Flow ◽  
Collision Process ◽  
Dynamical Behaviors ◽  
Mode A ◽  
Compound Droplet

A compound droplet with its single inner droplet appears in a broad range of applications and has received much attention in recent years. However, the role of the inner droplet location on the dynamical behaviors of the compound droplet is still not completely understood. Accordingly, the present study numerically deals with the eccentricity of the compound droplet affecting its colliding behaviors with the other droplet in a simple shear flow. The solving method is a front-tracking technique that treats the droplet interface as connected elements moving on a rectangular fixed grid. Initially, two compound droplets assumed circular are placed at a distance symmetrically to the domain center and they come into contact, because of the shear flow, when time progresses. During the collision process, the inner droplet that is initially located at a distance to its outer droplet center circulates around this center. It is found that this rotation also contributes to the formation of the collision modes including the reversing, passing-over and merging ones. Starting from a passing-over mode, a transition to a reversing mode or a merging mode can appear when the inner droplets, in terms of their centroids, are closer than their outer droplets. However, the location of the inner droplet within the outer droplet only has an effect when the value of the Capillary number Ca is varied from 0.01 to 0.08. For Ca < 0.01 corresponding to the merging mode and Ca ≥ 0.16 corresponding to the passing-over mode, the inner droplet position has almost no impact on the collision behaviors of two compound droplets.

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