000232728 001__ 232728
000232728 005__ 20180317095011.0
000232728 0247_ $$2doi$$a10.1007/s10546-017-0287-5
000232728 022__ $$a0006-8314
000232728 02470 $$2ISI$$a000415143200001
000232728 037__ $$aARTICLE
000232728 245__ $$aA Modulated-Gradient Parametrization for the Large-Eddy Simulation of the Atmospheric Boundary Layer Using the Weather Research and Forecasting Model
000232728 260__ $$aDordrecht$$bSpringer$$c2017
000232728 269__ $$a2017
000232728 300__ $$a20
000232728 336__ $$aJournal Articles
000232728 520__ $$aThe performance of the modulated-gradient subgrid-scale (SGS) model is investigated using large-eddy simulation (LES) of the neutral atmospheric boundary layer within the weather research and forecasting model. Since the model includes a finite-difference scheme for spatial derivatives, the discretization errors may affect the simulation results. We focus here on understanding the effects of finite-difference schemes on the momentum balance and the mean velocity distribution, and the requirement (or not) of the ad hoc canopy model. We find that, unlike the Smagorinsky and turbulent kinetic energy (TKE) models, the calculated mean velocity and vertical shear using the modulated-gradient model, are in good agreement with Monin-Obukhov similarity theory, without the need for an extra near-wall canopy model. The structure of the near-wall turbulent eddies is better resolved using the modulated-gradient model in comparison with the classical Smagorinsky and TKE models, which are too dissipative and yield unrealistic smoothing of the smallest resolved scales. Moreover, the SGS fluxes obtained from the modulated-gradient model are much smaller near the wall in comparison with those obtained from the regular Smagorinsky and TKE models. The apparent inability of the LES model in reproducing the mean streamwise component of the momentum balance using the total (resolved plus SGS) stress near the surface is probably due to the effect of the discretization errors, which can be calculated a posteriori using the Taylor-series expansion of the resolved velocity field. Overall, we demonstrate that the modulated-gradient model is less dissipative and yields more accurate results in comparison with the classical Smagorinsky model, with similar computational costs.
000232728 6531_ $$aAtmospheric boundary layer
000232728 6531_ $$aLarge-eddy simulation
000232728 6531_ $$aSubgrid-scalemodelling
000232728 6531_ $$aWeather Research and Forecasting model
000232728 700__ $$0249094$$aKhani, Sina$$g256546$$uEcole Polytech Fed Lausanne, Wind Engn & Renewable Energy Lab WiRE, CH-1015 Lausanne, Switzerland
000232728 700__ $$0243661$$aPorte-Agel, Fernando$$g168244$$uEcole Polytech Fed Lausanne, Wind Engn & Renewable Energy Lab WiRE, CH-1015 Lausanne, Switzerland
000232728 773__ $$j165$$k3$$q385-404$$tBoundary-Layer Meteorology
000232728 909CO $$ooai:infoscience.tind.io:232728$$pENAC$$particle
000232728 909C0 $$0252260$$pWIRE$$xU12172
000232728 917Z8 $$x168244
000232728 937__ $$aEPFL-ARTICLE-232728
000232728 973__ $$aEPFL$$rREVIEWED$$sPUBLISHED
000232728 980__ $$aARTICLE