The effect of a lower boundary condition on the boundary-layer structure of an axisymmetric vortex

1978 ◽  
Vol 14 (4) ◽  
pp. 525-541 ◽  
Author(s):  
G. V. Rao ◽  
W. H. Raymond
Keyword(s):  
Boundary Layer ◽  
Boundary Condition ◽  
Layer Structure ◽  
Lower Boundary ◽  
Lower Boundary Condition ◽  
Boundary Layer Structure ◽  
Axisymmetric Vortex

The Impact of Horizontal Model Grid Resolution on the Boundary Layer Structure over an Idealized Valley

2014 ◽  
Vol 142 (9) ◽  
pp. 3446-3465 ◽  
Author(s):  
Johannes S. Wagner ◽  
Alexander Gohm ◽  
Mathias W. Rotach
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Layer Structure ◽  
Thermal Structure ◽  
Inversion Layer ◽  
Lower Boundary ◽  
Grid Resolution ◽  
Convective Boundary ◽  
Boundary Layer Structure ◽  
The Impact

The role of horizontal model grid resolution on the development of the daytime boundary layer over mountainous terrain is studied. A simple idealized valley topography with a cross-valley width of 20 km, a valley depth of 1.5 km, and a constant surface heat flux forcing is used to generate upslope flows in a warming valley boundary layer. The goal of this study is to investigate differences in the boundary layer structure of the valley when its topography is either fully resolved, smoothed, or not resolved by the numerical model. This is done by performing both large-eddy (LES) and kilometer-scale simulations with horizontal mesh sizes of 50, 1000, 2000, 4000, 5000, and 10 000 m. In LES mode a valley inversion layer develops, which separates two vertically stacked circulation cells in an upper and lower boundary layer. These structures weaken with decreasing horizontal model grid resolution and change to a convective boundary layer over an elevated plain when the valley is no longer resolved. Mean profiles of the LES run, which are obtained by horizontal averaging over the valley show a three-layer thermal structure and a secondary heat flux maximum at ridge height. Strong smoothing of the valley topography prevents the development of a valley inversion layer with stacked circulation cells and leads to higher valley temperatures due to smaller valley volumes. Additional LES and “1 km” runs over corresponding smoothed valleys reveal that differences occur mainly because of unresolved topography and not because of unresolved turbulence processes. Furthermore, the deactivation of horizontal diffusion improved simulations with 1- and 2-km horizontal resolution.

Unsteady dynamics of turbulent flow in the wakes of barchan dunes modulated by overlying boundary-layer structure

2021 ◽  
Vol 920 ◽  
Author(s):  
Nathaniel R. Bristow ◽  
Gianluca Blois ◽  
James L. Best ◽  
Kenneth T. Christensen
Keyword(s):  
Boundary Layer ◽  
Turbulent Flow ◽  
Layer Structure ◽  
Boundary Layer Structure ◽  
Barchan Dunes

Abstract

scholarly journals Thermal boundary layer structure in convection with and without rotation

2020 ◽  
Vol 5 (11) ◽  
Author(s):  
Robert S. Long ◽  
Jon E. Mound ◽  
Christopher J. Davies ◽  
Steven M. Tobias
Keyword(s):  
Boundary Layer ◽  
Thermal Boundary Layer ◽  
Layer Structure ◽  
Boundary Layer Structure
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