Porosity Rendering in High-Performance Architecture: Wind-Driven Natural Ventilation and Porosity Distribution Patterns

Natural ventilation is one of the most essential issues in the concept of high-performance architecture. The porosity has a lot to do with wind-phil architecture to meet high efficiency in integrated architectural design and materialization a high-performance building. Natural ventilation performance in porous buildings is influenced by a wide range of interrelated factors including terrace depth, porosity distribution pattern, porosity ratio, continuity or interruption of the voids and, etc. The main objective of this paper is to investigate the effect of porosity distribution pattern on natural ventilation performance in a mid-rise building. One solid block and six porous residential models based on unit, row and combined relocation modules with different terrace depths (TD = 1.2, 1.5 m) were analyzed by computational fluid dynamics (CFD). The evaluations are based on grid sensitivity analysis and a validation of wind tunnel measurements. Investigations indicated that introducing the velocity into a solid block would enhance the building natural ventilation performance up to 64 percent compared to the solid case. However, it is demonstrated through simulations that the porosity distribution pattern as an architectural configuration has a significant effect on ventilation efficiency. Unit-Relocation models (U-RL) have approximately 1.64 times the mean airflow of the solid block, 1.1 times of Row-Relocation (R-RL) and 1.22 times of Combined-Relocation models (CO-RL). U-RL models are also able to achieve approximately 1.26 times the maximum air velocity inside the blocks compared to the solid case. This value is about 1.05 times of R-RL cases and 1.1 times of CO-RL cases. The results clearly indicated that porosity distribution pattern is a factor that could be modified by architects to fulfill most of architectural and environmental requirements.