B\'enard-Marangoni instability driven by moisture absorption

ORAL

Abstract

We describe experiments that exhibit B\'enard-Marangoni convection cells in hygroscopic fluids without external heating. B\'enard-Marangoni convection cells are classically driven by a heat source beneath a thin layer of fluid with a free-surface. External heating provides a reservoir of hot fluid to amplify the free-surface temperature perturbations which drive Marangoni flow; without the heat source, the system naturally damps the temperature fluctuations and stabilizes itself. By drawing water vapor from ambient air, certain hygroscopic fluids can generate their own internal heat source by exploiting an exothermic enthalpy of solution with water. We verify the origin of the instability by using different hygroscopic fluids. The dynamics of this unusual instability are measured as a function of the fluid and air properties of the system, and a mathematical model is developed to rationalize the results quantitatively.

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Authors

  • Sangwoo Shin

    Department of Mechanical and Aerospace Engineering, Princeton University

  • Ian Jacobi

    Department of Mechanical and Aerospace Engineering, Princeton University, Princeton University, Technion \& Princeton University

  • Jason Wexler

    Department of Mechanical and Aerospace Engineering, Princeton University, Princeton University

  • Howard A. Stone

    Princeton University, Department of Mechanical and Aerospace Engineering, Princeton University, Princeton Univ, Mechanical \& Aerospace Engineering, Princeton University, Princeton University, Complex Fluid Group