WINDWARD WINDBREAK EFFECTS ON AIRFLOW IN AND AROUND A SCALE MODEL OF A NATURALLY VENTILATED PIG BARN

Abstract

Wind tunnel tests of 1:20scale windbreak models placed in a windward position from naturally ventilated pigbarns were performed to examine the capability of windbreaks to trap air contaminants emitted from livestock buildings. Theairflow surrounding the windbreak and the building was measured. Dispersion of air contaminants was predicted with theproposed parameters PU, PV, and PW, which are related to airflow momentum in the leeward direction and to horizontal andvertical plume sizes, respectively. Windbreaks included a solid wall, a net screen, and another pig barn. With a solid wall asa windbreak, air emitted from the building was exhausted in the windward direction. Compared to a net screen or anotherbarn, the solid wall resulted in the lowest airflow momentum. A highconcentration odorous area was predicted to be locatedbetween the windbreak and the building. Sprinklers in this area could possibly trap the air contaminants. When a buildingwas placed in the windward position as a wind barrier, the dispersion of odorous air behind the leeward building was predictedto be the smallest compared to a solid wall and a net; moreover, a smaller plume width was seen. When a net screen was used,the airflow between the wall and the building moved only in the leeward direction.