Les analysis of impact of non-uniformity of building height in highly dense urban district on wind environment (part 1): Quantitative evaluation of drag force of urban district and streamwise momentum transport

Non-uniformity of building height has the effect of improving the quality of outdoor environment by increasing wind velocity at the pedestrian-level within a focused urban district. However, the urban district with non-uniform height causes more momentum loss of streamwise wind than an urban district with uniform height. Consequently this leads to decreased wind velocity in leeward areas of the focused area. In this study, LESs were applied to flowfields in two districts consisting of rectangular buildings with uniform and non-uniform heights, and the influence of the non-uniformity on drag force of urban district and streamwise momentum transport was quantitatively evaluated.