Discrete Dry Convective Entities: I Review

Abstract

Discrete convective entities are compact regions of fluid, generally turbulent, which penetrate homogeneous or stably stratified environments, otherwise at rest or in simple motion. They include: jets and plumes from steadily maintained sources of momentum and/or buoyancy; puffs, thermals and vortices from momentary sources; and starting jets and plumes from sources initiated and then maintained. They form a large class of flows with extensive applications in engineering and general fluid dynamics, although we are concerned here specifically with their atmospheric applications including convection in the planetary boundary layer and such insights as dry entities may provide into the dynamics of moist convection and cumulus clouds. Individual flows have been studied previously in great detail, especially jets and to a lesser extent plumes and thermals. There remain, however, puzzling and as yet inadequately explained features in some of the cases studied, while some other cases have either been little studied or are poorly understood.