CFD Analysis of the Impact of Building Shape on Natural Ventilation Effectiveness in High-Rise Buildings

With the increasing global emphasis on sustainability and high energy efficiency in buildings, natural ventilation is increasingly recognized as an effective passive strategy for reducing the cooling energy demand of buildings while ensuring indoor comfort and IAQ. Given its unstable nature and high dependence on building form, understanding and predicting how various aspects of building design impact natural ventilation effectiveness within the building becomes crucial to benefit it fully. This paper combines CFD analysis with building energy simulation to evaluate the effect of building shape on the cross-ventilation cooling potential of a real high-rise building in India. A comparative analysis of two distinct units with different shapes was conducted to evaluate the better shape for enhancing natural ventilation performance and thermal comfort. The results suggest proper orientation to prevailing winds, sizing and positioning of openings, optimization of indoor sections and interconnection between spaces are crucial in improving the effectiveness of wind-driven cross-ventilation. The unit with a higher ratio of inlet to outlet area (2:1 ratio) on the windward and leeward facades achieved a higher air exchange rate and average air velocity, ensuring an average 0.3 ℃ and a maximum up to 1.07 ℃ reduction in operative indoor temperature. The research outcomes provide valuable insights to optimize the building shape of high-rise buildings improving natural ventilation.