Effect of surfactants on stability of a moving interface in a Hele-Shaw cell.

ORAL

Abstract

Viscous fingering of immiscible fluids in a Hele-Shaw cell has been seen experimentally to be influenced by effects of surfactants on the interface between the fluids. A reasonable hypothesis is that Marangoni stresses due to a spanwise gradient in surfactant concentration are responsible. We analyze the problem of soluble surfactant transport in the Hele- Shaw cell and use matched expansions to derive effective boundary conditions including surfactant effects. These are then used to analyze the linear stability of a displacement flow. We find that Marangoni stresses due to differential adsorption of surfactant induce a secondary flow causing wavelength-dependent destabilization of the interface.

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Authors

  • Carolyn Gramlich

  • G.M. Homsy

    Department of Mechanical and Environmental Engineering, University of California-Santa Barbara, Department of Mechanical Engineering, University of California, Santa Barbara, Department of Mechanical and Environmental Engineering, University of California, Santa Barbara