Laboratory modelling of natural ventilation flows driven by the combined forces of buoyancy and wind.

This paper describes an innovative experimental technique that accurately reproduces natural ventilation flows, driven by the combined effects of stack and wind, at small scale in laboratory models of rooms or buildings. This technique provides a powerful tool for examining the performance of naturally ventilated buildings at the design stage as it may be used to predict quantitatively ventilation flow rates and temperature stratification under a wide range of climatic conditions. Following the success of saline modelling techniques to model stack-driven flows these techniques have now been extended to consider building ventilation under the combined effects of stack and wind. A full description of the experimental technique is given and it is shown that dynamical similarity is achieved between small-scale laboratory flows driven by combined stack and wind effects and those at full scale. Scaling laws used to transform the quantities from small scale to those at full scale are given.