A Theoretical and Experimental Study of Cellular Convection in Rotating Fluids

The stabilizing and cell-shape changing influence of a basic rotation upon thermally produced cellular circulations are developed in a first order, perturbation theory. The theoretical possibility of a special “overstable” oscillating mode in certain fluids under the influence of rotation is recognized. In this preliminary report, the theory obtained for ordinary convection is compared to results obtained in laboratory experiments with rotating cylinders of water, and the existence of the overstable oscillating mode is demonstrated experimentally. Several possible applications of the theoretical results to atmospheric convection are developed by means of numerical examples, including models that are consistent with the observed association of deep convection with cyclonic relative vorticity and the distribution of clouds in regularly spaced clear and cloudy areas.