Turbulent Prandtl number and characteristic length scales in stably stratified flows: steady-state analytical solutions

In this study, the stability dependence of turbulent Prandtl number (Pr_t) is quantified via a novel and simple analytical approach. Based on the variance and flux budget equations, a hybrid length scale formulation is first proposed and its functional relationships to well-known length scales are established. Next, the ratios of...

Parametrizing the Energy Dissipation Rate in Stably Stratified Flows

We use a database of direct numerical simulations to evaluate parametrizations for energy dissipation rate in stably stratified flows. We show that shear-based formulations are more appropriate for stable boundary layers than commonly used buoyancy-based formulations. As part of the derivations, we explore several length scales of turbulence...

Addressing the Grid-Size Sensitivity Issue in Large-Eddy Simulations of Stable Boundary Layers

We have identified certain fundamental limitations of a mixing-length parametrization used in a popular turbulent kinetic energy-based subgrid-scale model. Replacing this parametrization with a more physically realistic one significantly improves the overall quality of the large-eddy simulation (LES) of stable boundary layers. For the range...