Applied Mathematics Seminar

The Applied Mathematics Seminar usually takes place on Thursdays at 12:00 during term time in either Nuffield G13 or Lecture Theatre B Watson.

Spring 2020

Applied Mathematics Seminar Series: The role of surfactants on the interfacial stability of multilayer channel flows

  • Anna Kalogirou, University of Nottingham
  • Thursday 23 January 2020, 12:00
  • Biosciences 301

 

The linear and nonlinear stability of a two-layer surfactant-laden flow in a channel is examined using asymptotic modelling and direct numerical simulations (DNS). The surfactant molecules exist in one of the fluids only but they can get adsorbed at the interface or form micellar aggregates when their concentration is beyond a critical value. A mathematical model is formulated, consisting of governing equations for the hydrodynamics and appropriate transport equations for the surfactant concentration at the interface, the concentration of monomers in the bulk fluid and the micelle concentration. A primary objective of this study is to investigate the effect of surfactants on the stability of the interface, and in particular surfactants in high concentrations and above the critical micelle concentration. Interfacial instabilities are induced due to the acting forces of gravity and inertia, as well as the action of Marangoni forces generated as a result of the dependence of surface tension on the interfacial surfactant concentration. An asymptotic model is also derived in the long-wave approximation, comprising a system of highly nonlinear PDEs describing the evolution of the interface as well as interfacial, bulk and micelle surfactant concentrations. The identified linear instabilities are followed into the nonlinear regime by carrying out numerical computations of the model system as well as DNS . The underlying physical mechanism responsible for the formation of interfacial waves will be discussed, together with the complex flow dynamics (typical nonlinear phenomena associated with interfacial flows include travelling waves, solitary pulses, quasi-periodic and chaotic dynamics).

Title to be confirmed

  • Veronica Grieneisen, Cardiff University
  • Thursday 16 January 2020, 12:00
  • Biosciences 301

Abstract not available

Find out more

There is a complete list of talks in the Applied Mathematics Seminar on talks@bham.