Talk on May 23, 2013

Thursday, May 23, 2013 02:00 pm

Numerical simulation of incompressible flows with viscous fluid interfaces

Yuanjun Zhang (IGPM, RWTH Aachen)

Pure surface tension models for fluid interfaces are often not suitable for predicting droplet
behavior accurately.  Two mechanisms may be responsible for this discrepancy, namely sur-
face viscosity [1] and the so-called Marangoni effect [2].  The latter is closely related to the
presence of surfactants at the fluid interface.  It is known that both effects are strongly related
and should be considered in the modeling of two-phase flows.  Due to high tech new applica-
tions (e.g., particle-stabilized emulsion, new materials) systems with colloidal particles at liquid
interfaces have attracted a strongly growing interest in the past decade. In modeling the rheo-
logical properties of particle-laden interfaces one often introduces an effective surface viscosity.
The standard mathematical description of this is by means of the so-called Boussinesq-Scriven
model for the surface stress tensor[3]. In this talk we present standard models for describing the
Marangoni effect and surface viscosity.  Furthermore we treat numerical methods for the sim-
ulation of two-phase incompressible flow models that include the Boussinesq-Scriven surface
stress tensor. In order to validate our implementation, we compare numerical results with recent
theoretical predictions [4] for a plane Poiseuille flow problem with a droplet.

[1] M.J. Boussinesq, Ann.Chim.Phys. 29(1913), 349-357.
[2] V.G. Levich,Physicochemical Hydrodynamics, Prentice Hall, New Jersey, 1962.
[3] J.C. Slattery, Interfacial transport phenomena, Springer, 1991.
[4] J.T. Schwalbe et al., Soft Matter 17(2011), 7797-7804.

Time: 02:00 pm

Location: Room 149, Hauptgebäude, RWTH Aachen, Templergraben 55, 52056 Aachen