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Most previous studies clarify the interference effect between only two or three buildings, and very few assess the effect of a high-rise building within an urban block on its surrounding buildings. Accordingly, in this study, wind tunnel experiments were conducted on low-rise urban blocks having a high-rise building, and the wind pressure acting on the low-rise buildings was measured. For low-rise buildings located downwind of a high-rise building, an extremely low negative peak pressure was observed at the windward end of the roof at wind directions of approximately 30°. Further, a large-eddy simulation was applied to the flow field within an urban block, where extremely low negative pressure was observed. The strong negative pressure was generated because the detached flow at the windward corner of the high-rise building blew downward and struck the low-rise building located on the leeward side, and the flow became detached at the windward corner of the roof. The findings of this study indicate the importance of considering the wind-related damage to low-rise buildings caused by strong winds generated by high-rise buildings under extremely strong wind conditions. • Wind pressure on the low-rise buildings around a high-rise building was measured. • Negative pressure acting on the building roof behind a high-rise building was low. • Its negative peak value was extremely low at a wind direction of around 30°. • Wind flow that generated the strong negative pressure was analyzed by LES. [ABSTRACT FROM AUTHOR]

Abstract The urban configuration, which pertains to the arrangement and height of buildings, has strong relationships not only with pedestrian wind environment within the focused urban district but also with that in areas leeward of the focused area. Therefore, such influences on leeward areas should be considered concurrently when improving the wind environment within the focused area. In this study, a large-eddy simulation (LES) was applied to four types of flow field over urban-like roughness using two different building layouts: regular and staggered, and two different building height conditions: uniform and non-uniform. Periodic boundary conditions are imposed laterally and streamwise directions to simulate an infinite array in equilibrium flow field. Based on LES data, the vertical structures of the transport and dissipation of kinetic energy were analyzed. Negative effects of the increase the wind velocity and enhancement the outdoor ventilation at pedestrian-level within the focused area on the wind environment of the leeward area were evaluated quantitatively with respect to the energy dissipation rate of the kinetic energy within the focused area. Additionally, the normalized airflow rate was defined for evaluating the relationship between the total amount of kinetic energy dissipation and outdoor ventilation performance, and the relationship was investigated. Highlights • Constant flux was formed by setting the constant momentum to the upper boundary. • Dissipation occurred within twice the building height by resistance of roughness. • Kinetic energy was mostly lost at canopy height in uniform height case. • Dissipation was largely caused by high-rise buildings in the non-uniform case. • Dissipation and normalized airflow rate in urban areas are negatively correlated. [ABSTRACT FROM AUTHOR]