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- Title
Large-Eddy Simulation of a Katabatic Jet along a Convexly Curved Slope. Part I: Statistical Results.
- Authors
BRUN, CHRISTOPHE; BLEIN, SÉBASTIEN; CHOLLET, JEAN-PIERRE
- Abstract
Large-eddy simulation is performed to study a katabatic jet along a convexly curved slope with a maximum angle of about 35.5°. The design of this numerical simulation of turbulent shear flow is discussed, and a qualitative assessment of the method is proposed. The katabatic flow is artificially generated by ground surface cooling, and a stable atmospheric boundary layer with constant stratification is considered as a reference state. A quantitative statistical analysis is used to describe the present turbulent flow, with a focus on the outer-layer shear of the katabatic jet, which extends about 50mabove the jet maximum. The Prandtl model for a katabatic jet is applied to the present results, and revisited versions of the model found in the literature are discussed, with an emphasis on specific momentum and turbulent heat diffusion. The vertical and downslope variability of the turbulent kinetic energy budget is also discussed, and it is shown that advection and production contributions in the downslope direction are far from negligible in katabatic flows along curved slopes. A specific effect that the convex curvature has on the katabatic jet is one of centrifugal deceleration and an increase of the flow's turbulent production and turbulent intensity in the outer-layer shear. A strong thickening of the outer layer is also observed.
- Subjects
KATABATIC winds; LARGE eddy simulation models; TURBULENT shear flow; SURFACE cooling; ATMOSPHERIC boundary layer; TURBULENT diffusion (Meteorology)
- Publication
Journal of the Atmospheric Sciences, 2017, Vol 74, Issue 12, p4047
- ISSN
0022-4928
- Publication type
Article
- DOI
10.1175/JAS-D-16-0152.1