In case of cross ventilation through the large opening, it is well known that the inflow direction at the opening is not normal to the opening. Authors proposed the simplified prediction method of the inflow direction at the inlet opening and the airflow rate simultaneously. It is also well known that the use of general discharged coefficient values (CD) is not suitable for the calculation of cross ventilation rate. First reason is that the simple connection of the pressure loss coefficient of an opening (ƒÄ as the reciprocal of square CD) in series under-estimates the airflow rate. Secondly, CD varies according to the wind direction and the use of normal values over-estimates the airflow rate. Therefore, the proposed method uses the total pressure loss coefficient of the room (ƒÌ) instead of ƒÄ (or CD). The wind tunnel tests using a three-storied apartment building model with a room were conducted to investigate the inflow direction and the flow rate. The combination of the room positions and the external wind directions make various inflow directions at the inlet opening. The results were compared with the calculated results.
Hisashi Kotani is a research associate of Department of Architectural Engineering, Division of Global Architecture, Graduate School of Engineering, Osaka University, Japan.
He graduated from Osaka University in 1990 and earned M. Eng in 1992. He has been working for Osaka University since 1992. He earned Dr. Eng in 2003 from Osaka University. He has concurrently worked as a visiting scientist at University of Gavle, Sweden and Aalborg University, Denmark in 2003.
He has been studying natural and cross ventilation of buildings. His current interests are wind-induced cross ventilation through large openings. He is conducting many research projects about mechanical and hybrid ventilation as well.
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