"Wind affects tall buildings in various ways. Because of their height and width, whether as a single or a cluster of tall buildings, they impose several disturbances in urban wind patterns which, in turn influences their exterior and interior environmental performance. This research qualitatively investigates the performance of existing mid-modern 20th century tall (high rise) buildings in New York City when double-leaf-façades comprised of foil and textile membranes are grafted onto the buildings for the purpose of reshaping the building's form or "wind shadow", and thus changing its physical relationship to neighboring buildings with respect to airflow, in order to create favorable street and open-space microclimates. This theoretical work will examine whether a lightweight membrane double-leaf-façade with an aerodynamic (curvilinear surface) form could minimize adverse wind effects (downwind) of tall building structures such as, downwash vortex, gap / wake effects, and skimming flow which together creates, seasonal, local, and regional, physical impacts to urban geometry, ultimately determining the microclimate's characteristics that are formed within urban canyon geometry. Numerical analysis, i.e. Computational Fluid Dynamics (CFD) techniques are becoming more utilized in the initial investigations were fluid dynamics are examined, especially, with regards to wind analysis on tall buildings, since wind tunnel facility testing doesn't offer the flexibility and cost effectiveness in developing a design in its preliminary stages, computational fluid dynamics virtual wind tunnel domains are beginning to fill this niche. The simulations in this research only account for wind-induced airflow, as opposed to buoyancy-induced airflow which closely resembles results, attained from an Atmospheric Boundary Layer (ABL) wind tunnel facility where issues of natural ventilation (buoyancy) heat transfer aren't normally performed. Numerical simulations provides a significant opportunity, and a means, for observing wind behavior among a group of tall buildings to ascertain and predict, the potential environmental benefits of considering wind in their design. The study provided data results that support the potential use of double-leaf membrane facades in changing wind flow behavior among tall building structures."
