Wind Tunnel Experiment

In this study, we propose a method for forecasting heat emission effect in a small single-sided slit opening. In order to make a heat flux forecasting model, we carried out field measurement, wind tunnel experiment, and CFD analysis. In the field measurement, we measured heat flux and grasped the relationship of heat flux of the opening and airflow around the building surface. In the wind tunnel experiment, we measured airflow around the opening and grasped turbulence characteristics.

Variation of discharge coefficients with wind direction and opening position is one of the main factorsdebasing accuracy of cross-ventilation flow rate prediction. The local dynamic similarity model wasdeveloped to solve this problem, and previous studies had validated it for inflow openings. In thepresent study, two experiments were carried out to investigate its validity for outflow openings.

Cross ventilation is one of the most important techniques for maintaining a comfortable indoorenvironment in hot and mild seasons with less cooling energy. But, at present, it is difficult to designindoor environment under cross ventilation because there is insufficient knowledge to evaluate theeffect of cross ventilation quantitatively. Thus the full-scale model experiment has been done in a large wind tunnel to examine the airflow property in the cross-ventilated space.

The wind tunnel experiment is the major method for cross ventilation researches. Up to now no quantitative evaluation method nor standard has been produced. This research project is to develop the quantitative method to predict cross ventilation rate driven by wind. A specially designed wind tunnel is used in the project. Conventional wind tunnel experiment is carried out in parallel with scale models of building without openings.

With the purpose of evaluating validity of the application of CFO on the problems of cross-ventilation, numerical simulation was performed, using standard k- E model and two types of modified k-E models which improve evaluation accuracy in production term of turbulence energy, and also using LES, and the results were compared with those of the corresponding wind tunnel experiment. As a result, it was found that the defects of the model characteristic to the standard k- E model could be improved to a certain extent by application of the modified models.