The blockage rate for three kinds of nets commonly used in agricultural facilities was assessed by using the image acquisition and its relevant processing. By using both empirical relations presented by Idel’chik and Richards and Robinson, and the blockage rate obtained from the image processing, the pressure drop through the nets was predicted and also compared with wind tunnel experiment results. The results of the study showed that the blockage rate of the net was discriminated according to such factors as the magnitude of nets, the existence of inside threads, the thickness and number of threads. In addition, the blockage rate for the incident angle of 0° when the wind blew at the front had the range of 0.22－0.29 (0.22－0.32 when considering whole incident angles from 0° to 45° by 15°). For the nets with the blockage rate of about 30% or below, the prediction by the empirical relations of by Idel’chik and Richards and Robinson showed a little higher pressure drop overall than that of the wind tunnel test, but the use of the empirical relations and the blockage rate could be thought of as providing effectively meaningful guidelines for the safe design of agricultural facilities including nets because the wind tunnel test has been tedious and expensive. Further research and potential application on the prediction technique of the pressure drop, regarding both a subtle deformation by the wind and manufacturing methods with regard to the level of knots and the existence of inside threads, needs to be done for the nets with higher blockage rate.

서 론
재료 및 방법
    1. 네트 수집 및 크기 측정
    2. 폐쇄율 산정 방법
    3. 압력 강하 산정 방법
결과 및 고찰
    1. 네트의 폐쇄율
    2. 압력 강하 비교
적 요
사 사

• 염성현(국립농업과학원 안전재해예방공학과 연구사) | Sung-Hyun Yum (Researcher, Disaster Prevention Engineering Division, National Institute of Agricultural Sciences, Jeonju 54875, Korea)
• 강승희(전북대학교 항공우주공학과 교수) | Seung-Hee Kang (Professor, Department of Aerospace Engineering, College of Engineering, Jeonbuk National University, Jeonju 54896, Korea) Corresponding author
• 류희룡(국립농업과학원 안전재해예방공학과 연구사) | Hee-Ryong Ryu (Researcher, Disaster Prevention Engineering Division, National Institute of Agricultural Sciences, Jeonju 54875, Korea)
• 윤홍기(충청남도농업기술원 원예연구과 연구관) | Hong-Ki Yoon (Senior researcher, Research Division for Horticulture, Chungcheongnam-do Agricultural Research and Extension Services, Yesan 32418, Korea)
• 이우수(충청남도농업기술원 원예연구과 연구사) | U-Su Lee (Researcher, Research Division for Horticulture, Chungcheongnam-do Agricultural Research and Extension Services, Yesan 32418, Korea)
• 유영지(국립농업과학원 안전재해예방공학과 연구원) | Yeongji Yu (Assistant researcher, Disaster Prevention Engineering Division, National Institute of Agricultural Sciences, Jeonju 54875, Korea)