Numerical investigation of indoor airflow behavior in Bushehr’s Sa’adat School based on the Openings and corridors situation using CFD method

Background and objectives: Indoor air quality is one of the important factors related to the health and wellbeing of users, with passive technologies such as natural ventilation being crucial to improve air quality. Natural ventilation and air flow behaviour in different climates are, therefore, important to investigate, particularly in hot and humid areas where the need for the air flow is at its highest. Climatic demands are a key factor in spatial formations of traditional cities of Iran, with the hot, humid city of Bushehr being a prime example. The present article deals with mathematical investigations of the behaviour of the internal air flow prompted by external winds. Focusing on the openings in the traditional building of Bushehr’s Sa’adat school, it tries to highlight the role of the openings and semi-open corridors in responding the need to generate and direct the constant flow of air in the interior spaces.Methods: A hybrid method is used in the present research. In the first stage, by formulating an experimental strategy, the physical elements of the school (independent variables) were examined, and with the help of precise digital devices, the speed and direction of the air flow inside (dependent variable) was registered in a test period. Analyses were then done using CFD simulation strategy and using Gambit preprocessor and Fluent software (after proving the validity and reliability).Results and conclusion: The results show that the dominant west and north-west winds, break when they hit the west wall of the school and change direction to the sides and upwards. This collision is associated with an increase in pressure behind and above the wall, as well as an increase in speed behind the wall compared to the prevailing air flow speed. The lowest air speed and pressure is at the level close to the courtyard, and with the increase in height to the middle of the window comes an increase in the air flow. The location of the spaces, corridors, porticoes, and openings significantly affect the pattern of internal flows, and the special composition and physical characteristics of the side corridors cause the existing air inside the classrooms to be sucked outside prompting natural ventilation. Also, the flow in classrooms flanked by side corridors with suitable openings was measured at least 0.05 m/s on average.