Dynamics and Selection of Giant Spirals in Rayleigh-Bénard Convection

Abstract

For Rayleigh-Bénard convection of a fluid with Prandtl number $\sigma =1.4\mathrm{}$, we report experimental and theoretical results on a pattern selection mechanism for cell-filling, giant, rotating spirals. We show that the pattern selection in a certain limit can be explained quantitatively by a phase-diffusion mechanism. This mechanism for pattern selection is very different from that for spirals in excitable media.