Turbulence Modeling in Stratified Flows Subject to Advective Buoyancy Fluxes

The goal of this work is to examine in detail how turbulence evolves in the presence of both vertical stratification and horizontal (straining) buoyancy fluxes. Horizontal density gradients are a ubiquitous feature of estuarine and coastal flows, as are sheared velocity profiles. The combination of these two features produces a buoyancy flux which can be either stabilizing or destabilizing, depending on the orientation of the currents relative to the density gradient (see, e.g. Simpson et al. 1990). The research being pursued under this grant is seeking to develop robust parameterizations of turbulent mixing that can be used with circulation models and provide efficient and accurate solutions to the turbulent closure problem.