Two-dimensional numerical simulation of wind driven ventilation across a building enclosure with two free apertures on the rear side: Vortex shedding and “pumping flow mechanism”

Boundary layer wind tunnel modeling experiments on pumping ventilation through a three-story reduce-scaled building with two openings

“…The formation of the pumping ventilation is due to the periodic vortex shedding induced by the instability of the two shear layer from the building sides. According to our former publications on pumping ventilation, the periodicity of pumping flow was clearly observed for a large range of Re from 1.1×10 5 to 8.75×10 7 considered in our former studies (Zhong et al, 2018(Zhong et al, , 2019a(Zhong et al, , 2019b(Zhong et al, , 2020. It is widely accepted that the mean flow characteristics will be similar if the Reynolds number is large enough (Townsend, 1956).…”

“…It is revealed that two or more openings have better ventilation effectivity than one for the same total opening area (Graça and Linden, 2016). Zhong et al (2018) reproduced pumping flow through a rectangular building using 2D CFD simulation and considered the influence of upstream wind speed, side ratio of the building and opening separation on pumping frequency and ventilation rate. Considering that 2D simulations cannot predict real 3D flow structure, then carried out 3D CFD simulations on the pumping ventilation of an infinite tall building.…”

Review of calculating models of unsteady natural ventilation rate due to wind fluctuations

“…According to Daniel, 77 the following problems were not considered in the study of Zhong et al 78–82 :(1) The 3D structure of the pumping ventilation flow mechanism in buildings.(2) The influence of the vertical component of the wake region caused by the roof of the building.(3) The influence of the atmospheric boundary layer.…”

“…It measured in twodimensional vortex shedding ranges from 0.07 to 0.21, while in the three-dimensional situation, it ranges from 0.09 to 0.1. 77 Zhong et al 78 reconstructed the 'pumping' airflow using two-dimensional CFD simulation and analysed the effect of the inflow wind speed, side ratio and aperture separation on the ventilation. However, the impacts of the thickness of the ground boundary layer and roof shedding were not assessed in the two-dimensional model simulation.…”

“…According to Daniel, 77 the following problems were not considered in the study of Zhong et al [78][79][80][81][82] :…”