A comparison of CFD and full-scale measurements for analysis of natural ventilation

CFD modelling techniques have been used to simulate the coupled external and internal flow in a cubic building with two dominant openings. CFD predictions of the time-averaged cross ventilation flow rates have been validated against full-scale experimental data under various weather conditions in England. RANS model predictions proved reliable when wind directions were near normal to the vent openings. However, when the fluctuating ventilation rate exceeded the mean flow, RANS models were incapable of predicting the total ventilation rate. Improved results are expected by applying more sophisticated turbulence models, such as LES or weighted quasi-steady approximations.