Topology-optimized bidirectional wind catchers for unidirectional ventilation and contaminant removal in asymmetric urban building corridors

Abstract

Abstract

High-density urban development severely limits natural ventilation in building corridors, increasing exposure risks when Contaminant sources exist. This study applies topology optimization to design a bidirectional wind catcher that induces stable unidirectional airflow in confined corridors, thereby enhancing passive ventilation. A simplified three-dimensional corridor model was developed and evaluated through numerical simulations, with particular focus on wind catcher height and ambient wind speed. Results show that southerly winds drive corridor ventilation mainly through pressure differentials, which are effective at low wind speeds but become less stable as wind speed increases. In contrast, northerly winds rely on jet-induced entrainment, providing more robust ventilation at higher wind speeds. A generally effective unidirectional ventilation performance is achieved when the wind catcher height is sufficiently larger than the corridor height (approximately 2.5 times the corridor height in the present configuration). Moreover, this study demonstrates the feasibility of reliable directional ventilation under bidirectional winds and provides a transferable topology optimization framework for passive ventilation design in dense urban environments.