A theoretical model for structure inclination angles in stratified boundary layers: Connecting turbulent scaling and Monin–Obukhov similarity theory

Abstract

Although scaling laws and coherent structures have been well-studied in non-neutral boundary layer flows over a long period of time, a potential connection between them is still worth exploring. This work explores the structure inclination angle under non-neutral stratification conditions by way of a connection between turbulent scaling and Monin–Obukhov similarity theory. A model for theoretical structure inclination angles is built by extending the refined “turbulent eddy” model of H.-J. Huang [Phys. Rev. Fluids 4, 114702 (2019)] under stratified stability conditions. The variations in the inclination angle values with the stability parameter from the current model are found to be in good agreement with results from the literature, laboratory results, and atmospheric surface layer observations. In addition, the results show that increasing positive/negative buoyancy leads to increasing/decreasing inclination angles and steeper/moderate angles at higher wall-normal heights. This variation is parameterized and can be used to improve existing near-wall models.