Computational fluid dynamics analysis of wind-driven ventilation in a double-story terraced house sheltered by adjacent buildings

Natural ventilation (NV) is an effective method to enhance ventilation in enclosed areas or buildings without incurring any cost to fit in mechanical ventilation systems. In Malaysia, double- and triple-storey terraced houses account for a large share of residential properties. Hence, understanding the impact of NV on these types of houses is essential for achieving optimal air circulation and ensuring a healthy, comfortable living environment. The purpose of this study is to determine the optimal door-opening configuration for indoor ventilation in a typical Malaysian double-storey terraced house, under cross ventilation (CV) and single-sided ventilation (SSV), and to examine the influence of adjacent buildings. Computational fluid dynamics using OpenFOAM is used to evaluate ventilation on the house's ground floor under two prevailing wind directions: towards the front façade (forward wind) and towards the rear façade (backward wind). A validation study of a generic building block was conducted and compared against published experimental data. Our findings indicate that excluding upstream units leads to overestimations of approximately 100% to 150%, depending on indoor location. Additionally, CV configurations were significantly more effective than SSV configurations in terms of ventilation rate and area-weighted velocity. Under CV mode, wind enters the house through the opening at the back rather than the opening at the front, which faces the prevailing wind.