When the wind direction is parallel to the opening facade, the wind shear near the building opening generates turbulence and entrains air across the opening. This kind of shear-induced ventilation cannot be predicted by the orifice equation because the time-averaged pressure difference across the opening is close to zero. This study uses wind tunnel experiments and the tracer gas decay method to investigate the ventilation rate of shear-induced ventilation. The influences of opening area A. external wind speed U and wind direction on the ventilation rates Q, of single-sided and two-sided openings are systemically examined. The experimental results indicate that the dimensionless ventilation rate, Q(center dot) = Q/UA, of shear-induced ventilation is independent of the wind speed and opening area, and the value of Q. of two-sided openings is larger than that of a single-sided opening. In addition, a cosine law was used to predict the ventilation rate of building with two-sided openings under various wind directions, and the results are compared with the prediction of the multizone ventilation model COMIS. (C) 2011 Elsevier B.V. All rights reserved.
