INVESTIGATION OF SURFACE ROUGHNESS IMPACT ON MEAN WIND FLOW USING RNG k-ε MODEL
DOI:
https://doi.org/10.11113/jt.v78.5161Keywords:
Small-scale roughness, urban canopy flow, packing density, streamwise velocity, turbulent kinetic energy, renormalisation group k- ε modelAbstract
Wind flow in the urban boundary layer is influenced by both large- and small-scale surface roughness. In this study, Reynolds-averaged Navier-Stokes simulations using the renormalisation group (RNG) k-ε model were performed to study the wind flow in square arrays with small-scale roughness elements at the front and back of cubical obstacles at packing densities of 25.0% and 30.9%. The presence of small-scale roughness reduces streamwise velocity but increases turbulent kinetic energy. Moreover, small vortices are formed within the canopy because of small-scale roughness. The generated streamwise velocity profiles are similar at packing densities of 25.0% and 30.9%, but the drag coefficient is higher in the latter case. In brief, the impact of small-scale roughness on urban wind flow is considerable. The results of this study can contribute to future research on wind flow, particularly in the urban environment. Â
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