Random Walk 모형을 이용한 비균질 다공성 매질에서의 지하수 흐름과 용질이동에 대한 수치적 연구 = A Numerical Study of Fluid flow and Solute Transport in Heterogeneous Porous Media using Random Walk Model

다국어 초록 (Multilingual Abstract)

Groundwater pollution can be expected as a necessary result of allowing for nonsystematic groundwater exploitation and management. This problem is confirmed by reports and press releases. It is important that we understand the moving routes of pollutants because the effects of polluted groundwater last longer than surface water's effects.
This study uses TBM(Turning Bands Method), a geostatistical method for generating spatiallycorrelated hydraulic conductivity and distribution coefficient's random distribution, calculates hydraulic head distribution for observing solute transport in the subsurface using Galerkin Finite Element Method, and calculates velocity distribution in each element from hydraulic head distribution. To solve the advection-dispersion-sorption equation numerically, this study uses the random walk particle tracking method that solves the equation by the large number of particles which are moved by dispersion and local velocity which is changed with space and time.
In order to observe the effects of correlation on hydraulic conductivity and distribution coefficient, this study carried out numerical simulation by giving a variety of which expresses correlation. The results show that longitudinal spatial moments in the positive correlation case are larger than the negative correlation case. This is caused by high hydraulic conductivity combined with high distribution coefficient in the positive correlation case, so the longitudinal spatial moment is larger than the negative correlation case.
In order to observe solute transport's alteration, this study carried out numerical simulation by giving a variety of hydraulic conductivity's correlation length,. The results show that longitudinal mass-center-displacement in the case of=15.0m is larger than the case of=5.0m. This is caused by a high correlation effect, so solute transport is enhanced, longitudinal mass-center-displacement and longitudinal spatial moment are enlarged.