Experimental measurements and computations of the wind-induced ventilation of a cubic structure

This paper presents the results of an experimental, theoretical and computational investigation of the wind-driven ventilation through a 6 m cube with openings on opposite faces. Measurements were made of the surface pressures coefficients and mean and total ventilation rates through the cube for the faces with the openings both normal and parallel to the wind. These measurements were then compared with a number of methods for the prediction of mean and fluctuating ventilation rates. For the normal configuration the mean component of ventilation was considerably greater than the fluctuating component, whilst for the parallel configuration the mean component was close to zero, and the ventilation was dominated by the fluctuating component. For the normal configuration the standard discharge coefficient method was shown to significantly underpredict the mean ventilation rate. A CFD calculation was however reasonably accurate in this regard. By contrast, for the parallel configuration the use of the standard discharge coefficient resulted in a small overprediction of the measured values of ventilation rate. The relative magnitudes of the ventilation produced by the various fluctuating flow mechanisms (broad banded, resonant and shear layer) were established, and methods of calculating the total ventilation rate from the mean and fluctuating components discussed. Finally, a simple method is presented for the estimation of shear layer ventilation.