• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.1
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• pp.46-51
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• 2009

This paper presents results from field studies carried out to monitor off-target droplet movement of endosulfan insecticide applied to the Korea chestnut tree area. As a results, mean airborne drift values were recorded 25m as average from downwind of a single flight line(sample line) in mountain terrain and mean effective swath width was recorded 19.5m as average in a plain. In terms of characteristics of geography of Korea aerial application is mainly carried out in mountain terrain. The equipment, weather conditions, and appropriate aerial spray technic are required for effective aerial application. In particular, the pilot can get effective results when he only sprays with consideration of environment factors since there is much turbulence in mountain terrain. Eventually, the most effective factor of droplets drift is to estimate the local weather conditions exactly.

• Journal of Wetlands Research
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• v.16 no.1
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• pp.41-50
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• 2014

The purpose of this study is to evaluate the High Rate Spiral Clarifier(HRSC) availability for the improvement of polluted retention pond water quality. A lab scale and a pilot scale test was performed for this. The fluid flow patterns in a HRSC were studied using Fluent which is one of the computational fluid dynamic(CFD) programs, with inlet velocity and inlet diameter, length of body($L_B$) and length of lower cone(Lc), angle and gap between the inverted sloping cone, the lower exit hole installed or not installed. A pilot scale experimental apparatus was made on the basis of the results from the fluid flow analysis and lab scale test, then a field test was executed for the retention pond. In the study of inside fluid flow for the experimental apparatus, we found out that the inlet velocity had a greater effect on forming spiral flow than inlet flow rate and inlet diameter. There was no observable effect on forming spiral flow LB in the range of 1.2 to $1.6D_B$(body diameter) and Lc in the range of 0.35 to $0.5L_B$, but decreased the spiral flow with a high ratio of $L_B/D_B$ 2.0, $Lc/L_B$ 0.75. As increased the angle of the inverted sloping cone, velocity gradually dropped and evenly distributed in the inverted sloping cone. The better condition was a 10cm distance of the inverted sloping cone compared to 20cm to prevent turbulent flow. The condition that excludes the lower exit hole was better to prevent channeling and to distribute effluent flow rate evenly. From the pilot scale field test it was confirmed that particulate matters were effectively removed, therefore, this apparatus could be used for one of the plans to improve water quality for a large water body such as retention ponds.