MS-Micro 4: Improved treatment of roughness variations.

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MS-Micro 4 Improved treatment of roughness
variations. Wensong Weng a, Peter A Taylor a,b,
Jim Salmon b a Department of Earth and Space
Science and Engineering, York University, 4700
KeeleStreet, Toronto, Ontario, Canada M3J 1P3 b
Zephyr North Canada Ltd, 850 Legion Road Unit 20,
Burlington, Ontario, Canada L7S 1T5
Based on the 1-D planetary boundary layer model
of Weng and Taylor (2003) with E-l turbulence
closure, 2-D (Weng et al, 2009) and 3-D
numerical models are developed to study the
atmospheric boundary-layer flow over single or
multiple changes in surface conditions as well as
general spatial distributions. Topographic
effects are estimated using the MSFD model and
the perturbations caused by roughness and
topography are linearly superimposed. Effects of
thermal stability can also be included. Sample
results for winds blowing off-shore over lake
Ontario (a possible offshore wind farm site) are
shown in Figure 1 (no topography).
Offshore flow from Toronto over Lake Ontario?
Neutral stratification. Note increase at 80m
requires fetch gt 1 km
Bolund (from the Risö web site)
BOLUND results with an MS-Micro 4 prototype The
results submitted were from the combination of a)
a 2-D NLMSFD model and a 2-D roughness change
model b) a 3-D MSFD model and a 3-D roughness
change model. Results with the 3-D roughness
(only) model are also shown below, for Case 1.
Input z0 field
Contour plot of fractional speed-up caused by
roughness variations at z 2 m above ground
Along the line y 0.
References Weng, W. and Taylor, P.A., 2003 On
modelling the one-dimensional atmospheric
boundary layer. Boundary-Layer Meteorol. 43,
273-286. Weng, W., Taylor, P.A. and Salmon, J.R.,
2009 A 2-D numerical model of boundary-layer
flow over single and multiple surface condition
changes. J. Wind Eng. Ind. Aerodyn. (2009),
doi10.1016/j.jweia.2009.10.006