CFD simulation of pumping ventilation with two asymmetrically arranged openings on the rear wall in a three-story isolated building

Pumping ventilation, driven by periodic vortex shedding, can effectively improve the ventilation rate of singlesided ventilation. Previous studies on pumping ventilation mainly considered symmetric opening conditions, while the asymmetric opening distribution has not been well studied. Therefore, this study investigates the pumping ventilation of an isolated three-story building with asymmetric opening conditions using computational fluid dynamics (CFD) simulations. Unsteady Reynolds-averaged Navier-Stokes (URANS) method with SST k-omega turbulent model is adopted to conduct the CFD simulations. The effects of horizontal translation distances, internal partitions, and inter-floor interference on time-averaged and fluctuating ventilation rates are investigated. The simulation results show that the mean ventilation rate is larger than the fluctuating ventilation rate. The mean ventilation rate increases while the fluctuating ventilation rate decreases with the increase of the horizontal translation distance. In addition, the internal partition decreases the pumping ventilation rate primarily by reducing the fluctuating ventilation rate rather than the mean ventilation rate. Furthermore, the ventilation rates of the 2nd floor are promoted by simultaneous pumping ventilation of the 1st and 3rd floors compared to the situation that only the 2nd floor is ventilated. The ventilation rates of the 1st floor are the largest, and of the 3rd floor are the lowest. The findings of this study benefit the deeper understanding of pumping ventilation and provide theoretical guidance on the opening designs of multi-story buildings for better ventilation efficiency.