SOIL EROSION PREDICTION IN DRY FIELD USING COMPUTATIONAL FLUID DYNAMICS SIMULATION

The purpose of this study was to predict wind erosion in dry field in order to alleviate the wind-blown soil problems thereafter. A well-known computational fluid dynamics (CFD) simulation was utilized to predict soil erodibility under changeable wind flows over complex terrain by coupling the erosion mechanism. The erosion mechanism was investigated by field measurements and derived as a modified form of the WEQ (wind erosion equation) to represent short-term wind erosion. The multiple linear regression analysis of repetitive experimental data derived the wind erosion equation, which showed a good agreement with the measured data with R² = 0.61. For CFD modeling of topographical effects, the land cover data was linked to the CFD simulation by mapping the virtual porosity and using user-defined functions. The CFD simulation coupled with the regression model produced useful results concerning spatial distributions of soil erodibility, erodible area and soil erosion over complex terrain according to various wind directions. In target area, north wind generated the largest wind erosion, followed by east, south and west winds, while the largest erodible area was shown when the wind came from the west, followed by east, south and north winds. The largest wind erosion under the north wind was 32.7 kg min^-1 which was 1.7 times larger than the smallest in the west wind. Therefore the north wind generated strong wind erodibility over the small areas while the west wind generated weak wind erosion over wide area. This study also expects that the CFD simulation coupled with the wind erosion equation will be a valuable tool to evaluate and design various wind erosion prevention measures by simulating their performances as well as to establish effective and economical plans and decisions for crop production.