On the turbulence in negatively Buoyant Jets

Negatively buoyant jets (NBJ) have been investigated with both a laboratory simulation (with a Feature Tracking Velocimetry, FTV, technique, to measure velocity fields) and a numerical simulation (with an Immersed Boundary method, in which the velocity fields are computed by a DNS method and the concentration by a LES method).This phenomenon can be found in a number of practical applications, e.g. the sea discharge of brine from desalination plants through submerged outfalls, oil or gas drilling facilities and mineral salt industries e.g. from leaching of mineral salts domes, gypsum or acidic wastes from fertilizer factories, etc.. These jets are typically released upwards, with a certain angle on the horizontal, to increase the path before to sink in the seafloor, to maximize the dilution, therefore the NBJs are initially driven from a source of both momentum, so behave basically as simple jets, far from the outlet the buoyancy prevails, bending the jet similar to a plume. To understand the processes that govern the dilution is important study the turbulent mixing and the entrainment. In this work are presented the results, under a large range of conditions (e.g. angle of the diffuser, density of the brine, release into a stagnant environment), will be shown; in particular, first order statistics, to study the characteristic dimensions of the jet. The second and third order statistics, to study the turbulent quantities.