Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
293661 | Journal of Wind Engineering and Industrial Aerodynamics | 2012 | 8 Pages |
We investigate the effect of flow unsteadiness on the mean wind flow pattern in an idealized urban environment. To that extent, steady RANS and unsteady LES simulations of the flow around a city-block are conducted for various ambient wind directions. Our simulations reveal that the selected modeling approach can have a significant effect on (i) the mechanisms causing air exchange between the regions above and below roof level, (ii) the spatial distribution of the time-averaged exchange fluxes, and (iii) the total amount of air exchange. For some specific cases, the modeling approach even has a larger impact on the predicted air exchange rate than the ambient wind direction. These results are of key-importance to researchers and engineers involved in simulations of flow in the urban neighborhood.
► Detailed comparison between steady RANS and unsteady LES simulations. ► Analysis of flow around a city-block for various ambient wind directions. ► Different modeling approaches show to favor different exchange mechanisms. ► The modeling approach might have more impact on the results than the wind direction.