Effects of Wind Shields on Pedestrian-Level Wind Environment around Outdoor Platforms of a Megatall Building

A thousand-meter-high megatall building, which consists of three tear-drop-shaped towers arranged in an equilateral triangle and a central circular tower, has ten outdoor platforms along the height at an interval of 100 m to connect the four towers. As the pedestrian-level wind environment around the outdoor platforms of high-rise buildings has been less studied for higher incoming wind speeds than those of the ground wind, it is necessary to conduct the related research and evaluations of the pedestrian-level wind environment around outdoor platforms to ensure pedestrian comfort and safety. First, based on the flow field analysis of the megatall building model, potential aerodynamic measures are proposed to improve the pedestrian-level wind environment of outdoor platforms. Then, the wind tunnel test and CFD simulation of outdoor platforms are conducted with five aerodynamic measures, and an averaged adjustment coefficient is put forward to establish the link between the full model and the sub-configuration model for the wind speed amplification factor, Ri, greater than 1.0, so the data obtained from the wind tunnel test can be transformed for further assessment of the pedestrian-level wind environment. Finally, the Lawson criterion was used to quantitatively analyze and compare the effects of five aerodynamic measures to improve the wind environment, thus providing a design that satisfies the requirements of "wind comfort" and "wind safety" for the thousand-meter-high megatall pedestrian platform. This study contributes to the further understanding of pedestrian-level wind environment characteristics of outdoor platforms and the potential aerodynamic measures to improve wind comfort and wind danger.