Effect of wind direction on natural ventilation in a multiple-room house via field measurements and numerical simulations

Abstract

To investigate the influence of wind direction on multi-zone natural ventilation, we conducted long-term field measurements (FMs) in two rooms of an experimental house exposed to multi-directional winds. The computational fluid dynamics (CFD) simulation results of velocities and concentration fields in and around the house were compared with the FM results. The latter displayed significant variability in air changes per hour (ACH) depending on the wind direction, with the highest ACH being approximately 2.6 times the lowest ACH for both rooms. The CFD simulations satisfactorily reproduced the general trend of the wind direction influence on the ACH. We then compared the obtained results with those for a single-room (Volume 1 only) condition. Here, FMs indicated that including the adjacent Volume 2 with an opening typically increased the ACH of Volume 1 by an average of 83%. However, CFD simulations revealed that the ACH did not increase substantially in certain cases, depending on the positional relationship between the openings and impinging or separation flows around the house; this resulted in insufficient pressure differences or ventilation short circuiting within the house. Thus, when planning natural ventilation in multi-room buildings with multiple openings, consider the impact of wind direction.