A numerical and experimental study of turbulent single and multiphase forced plumes and jets at moderate Reynolds numbers

Flows where a narrow body of fluid, carried by initial momentum or buoyancy, entrains an ambient fluid are common in the environment. Volcanoes, smoke exiting a chimney or rising from a forest fire, tornadoes and deep water oil spills are just a few examples. If the main driving force is momentum we term such a flow a jet. On the other hand, if the main driving force is buoyancy we typically refer to the flow as a plume. Perhaps more common, initial momentum and buoyancy are both present in which case we can refer to the flow as either a buoyant jet or a forced plume. Forced plumes can be either single phase, where buoyancy is caused by either a difference in temperature or some other scalar phenomenon, or multiphase where buoyancy is due to the injection of particles, bubbles or drops of material other than the ambient fluid into the flow.;In this study single and multiphase jets and plumes will be examined. A laminar study will be presented which examines the effect of the addition of a small amount of nonzero angular momentum to jets and plumes. The results of direct numerical simulations of a pure jet, a pure plume and a forced plume, in the turbulent, moderate Reynolds number regime are presented and compared. Each simulation was run long enough so that time averaged third order statistics converged, allowing each term of the turbulent kinetic energy equation and Reynolds stress transport equations to be calculated directly. The results of laboratory experiments of a pure jet and multiphase plume, conducted at Ecole Nationale Superieure De Mecanique et D'Aerotechnique (ENSMA) located in Poitiers, France will be presented. Preliminary results of multiphase plume simulations using the Equilibrium-Eulerian technique will be discussed.