Reduced-dimension model for the Rayleigh-Taylor instability in a Hele-Shaw cell

Abstract

In this thesis we present a reduced-dimension model for the density-driven hydrodynamic Rayleigh-Taylor instability. We motivate the project with experimental findings of a little-understood stabilizing effect of geometry and deviations of measured instability wavelength from theoretical predictions. We present novel methods of data analysis for the experimental data. We then present a reduced-dimension model for the governing equations of the system, Stoke's equations and Fick's law, using polynomial trial functions. We discuss the results and conduct a linear stability analysis of the reduced system. We compare the model to a finite element simulation of the full governing equations using COMSOL, and propose an optimization framework for the basis functions of the reduced model. The reduced model helps in developing physical intuition for the behavior of the instability in this confined geometry, and understanding the effects of certain parameters that are difficult to study experimentally or by simulating the full equations.