Applying the local dynamic similarity model and CFD for the study of cross-ventilation

The Local Dynamic Similarity Model (LDSM) is a ventilation model for predicting the discharge coefficient and the inflow angle at the opening of a cross-ventilated building. This model requires a dynamic pressure generated by the wind velocity component tangential to the opening in addition to wind pressure. Also, total pressure, wind pressure, static pressure, room pressure and inflow velocity components are needed for model validation. Under cross-ventilation, it is rather difficult to measure these parameters, especially the total pressure and the velocity components at the opening, as the inflow angle is not known a priori. Therefore, an alternative was sought. This study applied a CFD method to determine the required parameters as a way of using the local dynamic similarity model. The CFD method had been validated with experimental results before the CFD data was used for LDSM. Good agreement was obtained between CFD and LDSM. Consequently the LDSM was also verified by CFD and it was viable to combine LDSM and CFD for the study of cross-ventilation.