Modeling of Mixing by Turbulent Jet in Stably Stratified Fluid

Abstract

A model that describes the density-profile evolution in a confined region with a stably stratified fluid, where mixing is induced by a circular, nonswirling turbulent jet discharged vertically down into the fluid is presented here. The interaction between the downward-moving jet and a resulting rising plume is modeled through a coupled system of equations that encompasses integral equations for volume, momentum, and buoyancy conservation for the jet and plume, respectively. A schematized flow pattern in the ambient fluid is employed to determine the effect of the jet/plume mixing on the density-profile evolution, and a diffusion equation is used to describe additional mixing processes in the ambient fluid outside the jet/plume region. The model is validated with experimental data on the density-profile evolution in a rectangular container produced by a mixing jet, and the calculations compare favorably with data for higher values on the densimetric Froude number. The mixing is underestimated for lower values on the Froude number.