Interaction Between a Discrete Downdraft and a Rotating Environment

Abstract

Laboratory experiments with negatively buoyant thermals in a rotating fluid show that vortex forming interactions occur over a considerable range of buoyancies and rotation rates. The interactions are not strongly dependent on the presence of a bounding surface for attachment of the vortex. Observed enhancement of downdraft velocity and suppression of entrainment by the interaction are in agreement with theory. It is suggested that a sudden downdraft in a rotating thunderstorm could create an upper level vortex potentially hazardous to aviation.