A WIND-TUNNEL STUDY OF WIND DIRECTION EFFECTS ON AIR-FLOW PATTERNS IN NATURALLY VENTILATED SWINE BUILDINGS

Smoke was used in a wind tunnel to visualize three dimensional airflow patterns inside a scale model of a naturally ventilated barn with gable roof and sloped ceilings. The design parameters studied were: 1) opening angle of rotating doors in the sidewalls; 2) centre versus side alley layout; 3) doors open on one side versus two sides of the barn; 4) solid versus partially open dividing wall at the building midlength; 5) ridge opening width; and 6) addition of openings in the barn endwalls. Each building configuration was tested with the building oriented at 0, 30, 60, and 90 degrees to the wind direction. Airflow patterns were observed and recorded on video tape. The optimum ventilation patterns were obtained for winds perpendicular to the building length. For parallel winds, the addition of windows in the end wall reduced the size of zones of slow smoke dispersion inside the model.