2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/213395We present a numerical study of a generalized two-dimensional Swift-Hohenberg model of spiral pattern formation in Rayleigh-Bénard convection in a non-Boussinesq fluid. We demonstrate for the first time that a model for convective motion is able to predict in considerable dynamical detail the spontaneous formation of a rotating spiral state from an ordered hexagon state. Our results are in good agreement with recent experimental studies of $CO_{2}$ gas. The mean flow and non-Boussinesq effects are shown to be crucial in forming rotating spirals.9 pages, 6 Figures (Postscript, appended)Condensed Mattertext