Pedestrian level wind speeds in downtown Auckland

Predictions of the pedestrian level wind speeds for the downtown area of Auckland that havernbeen obtained by wind tunnel and computational fluid dynamic (CFD) modelling are presented. The windrntunnel method involves the observation of erosion patterns as the wind speed is progressively increased.rnThe computational solutions are mean flow calculations, which were obtained by using the finite volumerncode PHOENICS and the k- e turbulence model. The results for a variety of wind directions are compared, andrnit is observed that while the patterns are similar there are noticeable differences. A possible explanationrnfor these differences arises because the tunnel prediction technique is sensitivity to gust wind speeds whilernthe CFD method predicts mean wind speeds. It is shown that in many cases the computational modelrnindicates high mean wind speeds near the corner of a building while the erosion patterns are consistent withrneddies being shed from the edge of the building and swept downstream.