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Estimation of Roughness Parameters Within Sparse Urban-Like Obstacle Arrays

# Estimation of Roughness Parameters Within Sparse Urban-Like Obstacle Arrays,10.1007/s10546-011-9590-8,Boundary-layer Meteorology,Byung-Gu Kim,Changhoo

Estimation of Roughness Parameters Within Sparse Urban-Like Obstacle Arrays
We conduct wind-tunnel experiments on three different uniform roughness arrays composed of sparsely distributed rectangular cylinders for the estimation of surface parameters. Roughness parameters such as the roughness length z 0 and zero-plane displacement d are extracted using a best-fit approximation of the measured wind velocity. We also perform a large-eddy simulation (LES) to confirm that four sampling points are sufficient to surrogate a space average above the canopy layer of the sparse roughness arrays. We propose a new morphological model from a systematic analysis of experimental data on the arrays. The friction velocity predicted by the proposed model agrees well with the peak value of the measured Reynolds shear stress $${(-\left)^{0.5}}$$. The proposed model is further validated in an additional wind-tunnel experiment conducted on a scaled configuration of a real urban area exposed to four wind directions. The proposed model is found to perform very well particularly in the estimation of the friction velocity, readily leading to a better estimation of turbulence, which is essential for an accurate prediction of pollutant dispersion.