Repository: Freie Universität Berlin, Math Department

Large-Eddy Simulation of inhomogeneous canopy flows using high resolution terrestrial laser scanning data

Schlegel, F. and Stiller, J. and Bienert, A. and Maas, H.-G and Queck, R. and Bernhofer, C. (2012) Large-Eddy Simulation of inhomogeneous canopy flows using high resolution terrestrial laser scanning data. Boundary-Layer Meteorology, 142 . pp. 223-243. ISSN 0006-8314 (Print) 1573-1472 (Online)


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The effect of sub-tree forest heterogeneity in the flow past a clearing is investigated by means of large-eddy simulation (LES). For this purpose, a detailed representation of the canopy has been acquired by terrestrial laser scanning for a patch of approximately 190m length in the field site “Tharandter Wald”, near the city of Dresden, Germany. The scanning data are used to produce a high resolution plant area distribution (PAD) that is averaged over approximately one tree height (30m) along the transverse direction, in order to simplify the LES study. Despite the smoothing involved with this procedure, the resulting two-dimensional PAD maintains a rich vertical and horizontal structure. For the LES study, the PAD is embedded in a larger domain covered with an idealized, horizontally homogeneous canopy. Simulations are performed for neutral conditions and compared to a LES with homogeneous PAD and recent field measurements. The results reveal a considerable influence of small-scale plant distribution on the mean velocity field as well as on turbulence data. Particularly near the edges of the clearing, where canopy structure is highly variable, usage of a realistic PAD appears to be crucial for capturing the local flow structure. Inside the forest, local variations in plant density induce a complex pattern of upward and downward motions, which remain visible in the mean flow and make it difficult to identify the “adjustment zone” behind the windward edge of the clearing.

Item Type:Article
Subjects:Mathematical and Computer Sciences > Mathematics > Applied Mathematics
ID Code:1108
Deposited By: Ulrike Eickers
Deposited On:14 Nov 2011 11:03
Last Modified:03 Mar 2017 14:41

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