Modelling of large openings.

The subtask 2 of Annex XX (Optimization of Air Flow Patterns Within Buildings) involved a research project called "Air Flows Through Large Openings In Buildings". The scope of this project was to test the range of validity of available algorithms, and where possible to develop new ones. This paper focuses on the new interzonal airflow studies which have been carried out in this frame. The research was based on three test rooms (respectively at the University of Libge, at INSA Lyon and at CSTB Sophia Antipolis) and mainly focused on natural convection ; the aim was to improve the knowledge and the numerical prediction of heat and mass transfer through doorways. This goal was achieved through a joint research effort which was based on the comparison of our experimental results. Moreover, these experimental results have been used to validate a C.F.D (Computational Fluid Dynamics) model developed at Concordia University. The main result consists of validated models to compute the mass flows in large openings assuming either isothermal air volumes or linear temperature profiles in both rooms ; the discharge coefficient that has been found is about 0.43. Local discharge coefficients have also been determined but this topic needs more studies ; C.F.D models, as those developed at Concordia University, seem well adapted to fulfill this task as long as they are validated.