Generalized Lagrangian Model for Buoyant Jets in Current

Abstract

A general Lagrangian jet model formulation is presented for an inclined buoyant jet in a current, with a three‐dimensional trajectory. The shear‐induced entrainment is computed as a function of the local densimetric Froude number and jet orientation, while the forced entrainment is taken as the ambient flow intercepted by the “windward” side of the buoyant jet. Model predictions are compared with both trajectory and tracer concentration data for a wide range of discharge and ambient flow conditions: horizontal buoyant jets in a coflow; vertical jets, oblique jets, and dense plumes in a cross flow; buoyant jets in a stagnant uniform or stratified fluid; and a horizontal buoyant jet in a perpendicular cross flow. The model is also consistent with the concept of asymptotic flow regimes, and reproduces the correct behavior in both the near and far field of a vertical momentum of buoyancy‐dominated jet in a cross flow. The connection of the model with traditional integral jet models is also discussed.