General integral formulation of turbulent buoyant jets in cross-flow

Abstract

The turbulent buoyant jet in a nonuniform cross-flow is formulated using a general integral method. The integral equations for the turbulent motion through the jet cross section are derived for a fixed control volume and expressed in vector form. In contrast to previous work, the new formulation does not require the a priori assumption of a velocity and concentration distribution. Coupled with a Lagrangian jet spreading hypothesis and the inclusion of added mass effect, the model is shown to predict correctly the properties of the asymptotic flow regimes in both the near field (straight jet and plume) and the far field (advected line puff and thermal). Predictions of the path-averaged jet properties are shown to be consistently supported by experimental data on visual trajectory and jet width, and centerline minimum dilution. The relation between the present formulation and previous Lagrangian/Eulerian models is also discussed.