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Large‐eddy simulations of neutrally stratified flow over surfaces with spatially varying roughness length
Author(s) -
Hobson J. M.,
Wood N.,
Brown A. R.
Publication year - 1999
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49712555803
Subject(s) - large eddy simulation , mechanics , surface finish , roughness length , surface roughness , closure (psychology) , flow (mathematics) , grid , mixing (physics) , turbulence , mean flow , homogeneous , constant (computer programming) , meteorology , geometry , geology , materials science , mathematics , statistical physics , physics , computer science , wind speed , thermodynamics , wind profile power law , quantum mechanics , economics , market economy , composite material , programming language
Large‐eddy simulations of neutrally stratified flow over a homogeneous surface (with constant roughness length) are used to help determine the requirements for a credible large‐eddy simulation of similar flow over a heterogeneous surface (with varying roughness length). It transpires that particular attention must be paid to simulating the unperturbed mean profiles correctly and to using appropriately high grid resolution. Results from heterogeneous large‐eddy simulations are then compared with those obtained using a first‐order mixing‐length closure model. Finally, the implications of the results for the validity of the effective‐roughness‐length parametrizations that are used in many numerical weather prediction models are considered.