土壤或含水層內之污染物傳輸為水文、地質、環境工程與土壤物理領域的科學家所關注，側向延散係數被認為多孔隙介質內污染物稀釋與反應物混合的主要因子。側向延散係數可由實驗室或現地試驗決定。文獻也指出側向延散係數可能是尺度相依，二維移流-延散方程式之解析解為實驗室或現地估算側向延散係數之快速、有效的工具。由於控制方程式係數為徑向變數的函數，因此解析求解圓柱座標系統之二維移流-延散方程式非常困難。此二年計畫之目的為發展解析技巧求解具常數延散係數或尺度延散係數之二維圓柱座標系統移流-延散方程式以描述圓柱形之非軸對稱溶質傳輸，此外計畫中將分別進行實驗室與現地試驗來呈現所發展解析解之應用。第一年發展具常數延散係數二維圓柱座標系統移流-延散方程式之解析解並進行實驗室土柱試驗，第一年發展具常數延散係數二維圓柱座標系統移流-延散方程式之解析解並進行實驗室土柱試驗，第二年發展具尺度延散係數二維圓柱座標系統移流-延散方程式之解析解並進行現地加入追蹤劑試驗之入滲試驗，本計畫所的結果有助於實驗室或現地估算側向延散係數。 ; Contaminant transport in soils and aquifers has become a matter of concern for scientist working in, hydrology, geology, environmental engineering and soil physics. The transverse dispersion has been identified as a key factor in the dilution contaminant and the mixing of reactants in porous media. Transverse dispersion coefficients can be obtained by using laboratory or field experiments. As is frequently cited, transverse dispersion coefficients can be also scale-dependenT. Analytical solutions to the two-dimensional advection-dispersion equations with constant or distance-dependent dispersion coefficients in cylindrical coordinates are fast and efficient tools for laboratory or field estimations of the transverse dispersion coefficients. Analytically solving the two advection–dispersion equation is extremely difficult because that the governing equation coefficients is dependent on the radial variable. The objective of this two-year project is to develop some analytical technique to solve the two-dimensional advection–dispersion equations in cylindrical coordinates with constant or scale-dependent dispersion coefficients for describing non-axisymmetraicl solute transport in cylindrical geometry. Additionally, the laboratory and field test with a tracer will be carried out to demonstrate the application of the developed analytical solutions. In the first year, the analytical solution to the two-dimensional advection–dispersion equations in cylindrical coordinates with constant dispersion coefficients will be derived and a laboratory soil column experiment will be performed. In the second year, the analytical solution to the two-dimensional advection–dispersion equations in cylindrical coordinates with scale-dependent dispersion coefficients will be developed and a field infiltration test with a tracer will be conducted. The results from this project will be useful in laboratory and field determination of the transverse dispersion coefficients. ; 研究期間 9708 ~ 9807
