Abstract

An extensive study of convection in ethanol-water mixtures heated from below in cylindrical geometry is presented. Two mixtures, with 25.0-wt.% and 1.1-wt.% ethanol concentrations are studied. These mixtures have nearly identical negative separation ratios and exhibit a subcritical bifurcation to traveling waves. During the linear regime, while the radially traveling wave amplitude is small, convection patterns can be decomposed into independent azimuthal modes. The symmetry of the pattern depends strongly on the radial aspect ratio of the cell, In both mixtures, even azimuthal modes are preferred for = 11.53 and = 11.44, while for = 10.91, odd nodes dominate. Demodulation of the time series of each mode's amplitude is used to extract the spatial and temporal profiles of the in-and out-going waves. Solutions of the Ginzburg-Landau type equation describing propagating waves are fit to these …

Date

November 12, 1995

Authors

Kristina Lerman

Institution

University of California, Santa Barbara