Turbulent Jets and Plumes

Abstract

Turbulent jets are fluid flows produced by a pressure drop through an orifice. Their mechanics, although studied for over fifty years, has recently received research attention that has resulted in a much improved understanding of the process by which they entrain surrounding fluid. Turbulent plumes are fluid motions whose primary source of kinetic energy and momentum flux is body forces derived from density inhomogeneities. Plumes have not been studied in the same detail as jets but nevertheless there have been some recent gains in the understanding of their mechanics. In this article we will review this progress, especially in relation to how jets and plumes interact with environmental factors, such as density stratification or uniform motion of the ambient fluid. As will become evident, many problems remain and, in some circumstances, we simply cannot describe precisely what does occur. In such cases we will try to provide current references and suggest approaches for future research.