Odor dispersion from road emissions were investigated using CFD (Computational Fluid Dynamics). The Shear Stress Transport k-ω model in FLUENT CFD code was used to simulate odor dispersion around the road. The two road configurations used in the study were at-grade and fill road. Experimental data from the wind tunnel obtained in a previous study was used to validate the numerical result of the road dispersion. Five validation metrics are used to obtain an overall and quantitative evaluation of the performance of Shear Stress Transport k-ω models: the fractional bias (FB), the geometric mean bias (MG), the normalized mean square error (NMSE), the geometric variance (VG), and the fraction of predictions within a factor of two of observations (FAC2). The results of the vertical concentration profile for neutral atmospheric show reasonable performance for all five metrics. Six atmospheric stability conditions were used to evaluate the stability effect of road emission dispersion. It was found that the stability category D case of at-grade decreased the non-dimensional surface odor concentration smaller 0.78~0.93 times than those of stability category A case, and that F case decreased 0.39~0.56 times smaller than those of stability category A case. It was also found that stability category D case of filled road decreased 0.84~0.92 times the non-dimensional surface odor concentration of category A case and stability category F case decreased 0.45~0.58 times compared with stability category A case.

본 연구에서는 SMS 모형을 이용하여 하천에 유입된 오염물질의 이송 및 확산 특성을 파악하기 위하여 실제 흐름에 적용하였다. 연구대상 수로구간은 한강하류부인 반포대교에서 가양대교까지를 실험하였으며, 수치모형으로는 RMA-2와 RMA-4를 사용하였다. RMA-2 모형을 통해 수치모의 결과와 실제 흐름에서의 확산범위 및 확산에 영향을 미치는 확산계수변화에 따른 농도 분포를 비교 분석하였고, RMA-4 모형을 통해 오염물질이 유입되었을 때 확산규모 및 이송특성을 분석하였다. 이 때의 경계조건으로 사용되는 유량 및 수위자료는 갈수기 기간을 선정하여, 한강 홍수통제소에서 제공하는 자료를 사용하였다. 수치모의 결과 갈수기 기간의 오염물질의 확산특성의 경우 확산계수의 영향을 거의 받지 않으며, 오염물의 도달속도는 오염물질이 유입된 지점에서 하류부로 갈수록 감소하였다.

The quantitative study of the groundwater contamination in a porous media is a difficult task. For complex problems, numerical solutions are the most effective means to study the movement of contaminants in the groundwater. The solute transport model used in this study has proved to be an efficient tool to model contaminant transport for complex problems. The model demonstrates its effectiveness in reproducing the contamination by chlorides of the roundwater at the landfill site due to leachate from the wastes. It describes the two dimentional solute transport and alteration of the water quality and forecasts the contamination for different management alternatives of the landfill. The model also indicates how the groundwater contamination can be contained within the Lowry site if a barrier is constructed downstream of the disposed wastes.

A Lagrangian dispersion model has been developed to study the transport of atmospheric pollutants over the southern Korean peninsula on sunny summer days. A mesoscale atmospheric model has been employed to provide the wind fields and information for turbulent diffusion for the calculation of trajectories using a conditioned particle technique. The model has been applied to the simulation of trajectories transport of atmospheric pollutants emitted from five sources in the coastal locations under various synoptic scale winds. Under calm synoptic scale condition, the particles emitted during daytime are mixed vertically and transported toward inland by sea-breeze, according to the model simulation. The particles are then transported upward at the sea-breeze front or by the upward motion over the mountain, and some particles show tendency of returning toward the coast by the return flow of the sea-breeze circulation. The particles are found to remain over the peninsula throughout the integration period under calm synoptic scale condition. When there is westerly synoptic scale wind, the particles emitted in the west coast can reach the east coast within a day or faster depending on the speed. With a synoptic scale southerly wind of 5 m/s, most of the particles from the five sources are advected toward inland during daytime. During nighttime, significant portion of particles released in the west coast remains over the land, while most particles released in the east coast move toward the sea to the east of the middle peninsula.