HR: 15:05h
AN: H22G-06 INVITED     [PDF]
TI: Land-Atmosphere Exchange Over Complex Terrain
AU: * Parlange, M B
EM: parlange@jhu.edu
AF: Center for Environmental and Applied Fluid Mechanics, Johns Hopkins University, Ames Hall 3400 N. charles St., Baltimore, MD 21218 United States
AU: Bou-Zeid, E
EM: eliebz@jhu.edu
AF: Center for Environmental and Applied Fluid Mechanics, Johns Hopkins University, Ames Hall 3400 N. charles St., Baltimore, MD 21218 United States
AU: Meneveau, C
EM: meneveau@jhu.edu
AF: Center for Environmental and Applied Fluid Mechanics, Johns Hopkins University, Ames Hall 3400 N. charles St., Baltimore, MD 21218 United States
AB: We study turbulent boundary layer flow over surfaces with varying roughness scales. The goal is to use LES results to formulate effective boundary conditions in terms of an effective roughness height and blending height. The LES are implemented with the dynamic Smagorinsky model based on the Germano identity. To account for geometric complexities associated with surface heterogeneity and its effects on the subgrid scales, the Lagrangian dynamic SGS model is implemented. A systematic array of simulations of flow over patches of differing roughness is performed, covering a range of patch length scales and surface roughness values. The simulated mean velocity profiles are analyzed to identify the height of the blending layer and to measure effective roughness lengths. We propose a simple expression for effective surface roughness and blending height knowing local surface patch roughness values and their lengths. Predictions of the model agree well with the LES results.
DE: 1800 HYDROLOGY
SC: Hydrology [H]
MN: 2003 Fall Meeting