Bio-inspired Fractal Parapet to Mitigate Rooftop Suction over a Low-Rise Building in High Winds

The significant damage experienced by roofing components of low-rise buildings in high winds necessitates the enhancement of their aerodynamic performance. Roof failure is often initiated at the windward roof edges and corners, due to peak suctions induced by flow separation and rooftop vortices. Past studies have explored using parapets on the roof to mitigate such peak suctions. Among the various parapets, the continuous porous parapet shows the most effective mitigation effects by disrupting rooftop vortex structures.

This research used a biomimetic approach to identify wind resilient strategies in nature and apply them to design a novel parapet. Fractal patterns have been used to control turbulence scales, increase turbulence intensity and reduce wind velocity. A cross-grid fractal-based porous parapet was designed to attempt further reduction in rooftop suctions. Wind tunnel tests of a 1:6 scaled low-rise building model was conducted to examine rooftop pressures of three configurations: no-parapet (control), porous parapet and fractal porous parapet. These configurations were tested at various wind directions to determine their effects on mitigating peak rooftop suctions. The results will provide insights into innovative flow control strategies by learning from nature.