Head-on collision of Newtonian drops in a viscoelastic medium

Abstract

Depending on the application, one needs to either stabilize or destabilize the interfacial properties of an emulsion. An aspect of the dynamics that governs the stability of emulsions in general is the drainage time of the film that is formed when two drops collide. In this work, we study the effect that viscoelasticity of the matrix fluid has on this drainage time of two Newtonian drops that perform a head-on collision under an applied macroscopic extensional rate. For the modeling of the viscoelastic matrix material, the Giesekus model is chosen. A cylindrical coordinate system is applied with imposed axisymmetry and the resulting equations are solved using fully resolved numerical simulations employing a finite element discretization. Our results show that viscoelasticity reduces the drainage time, which is a combined effect of three different stages.

Torsional fracture of viscoelastic liquid bridges

“…Here, the equations were discretized using a method described in ref. 57 and solved using the stabilized finiteelement method, whose mesh method, mesh movement and projection, time stepping, and stabilization can be found in ref. 58.…”

Dynamic stabilisation during the drainage of thin film polymer solutions

“…Yet, properties of the bulk fluids in confinement have also been identified as possibly playing an important role. [18][19][20][21] The most known effect is the occurrence of oscillatory structural forces normal to the interface due the confinement of finite sized structural elements, such as micelles, 22 nanoparticles 18 or polyelectrolytes. 23 The local structuring causes a difference in the osmotic pressure between the film and the surrounding plateau border which can balance the Laplace pressure difference and stabilises the film.…”