Abstract
Meteorological Observatory installs measuring boards on the even ground of open space to measure the amount of snowfall. However it is very difficult to evaluate the accurate amount of snowfall because of the influence of wind. In order to measure snow fall, it was tried to identify the inside airflow of octagon wind fence which was not influenced by wind. We performed computing fluid dynamics, wind tunnel test and field measurement of width and types of octagon wind break fence to analyze airflow inside of the fence. According to the result, dual fence was better than mono fence in wind speed reduction such as more than 50%. The fence whose wind fence wings were fixed on the surface showed better results than the fence detaching the wings from the surface. The reduction of the wind speed was the highest in the middle of the dual wind fence with 4m width. In wind tunnel test results, the fence attached to the surface with 4m width showed better wind speed reduction at the center of the inside than the fence with 6m width. In the actual measurement, 4m fence showed the best effects in wind speed reduction.