Density-driven flows: Plumes and Density Currents

Buoyancy-generated turbulence processes with substantial density variations within the flow are critical in oceanic systems. The talk highlights a universal framework to characterize density currents and turbulent plumes released from a source. Variable density effects in density currents and plumes alters the velocity field due to variation in density. Consequently the pathways for turbulence generation, mixing and transport are complicated than a passive scalar mixing. A large-eddy-simulation is used to simulate density currents and plumes released from a source.  In this talk, Favre-averaged turbulence transport equations for generalized compressible flows are presented within the context of density currents and plumes. A simplified conceptual turbulent model is presented.The study is focused on addressing a pivotal question: whether the kinetic energy spectrum follows the traditional inertial -$5/3$ spectrum, or displays a -$3$ buoyancy regime, or demonstrates a combination of both phenomena. Significant deviations from the inertial spectra are observed. New insights on the spectral transfer of energy, and turbulence mechanims for buoyancy-driven flows are presented