臺灣博碩士論文加值系統

地下水傳輸機制包含了移流、延散/擴散及複雜孔隙邊界，這些機制的混
合作用，造成了延散係數的尺度效應(scale effect)。本研究採用泰勒定
義的延散係數所發展出之廣義延散理論為基礎，選擇以特徵函數為主的「
自我伴隨」(self-adjoint operator)運算子，重新定義地下水的延散係
數，以解釋尺度效應。結果顯示：不僅僅延散係數是受水力傳導係數和起
始濃度分佈的影嚮，隨著時間的增加而增大並趨近一定值，是一暫態行為
；溶質的有效速度也隨著時間的增加而增大趨近一定值。由於時間之增大
，溶質流經之距離相對增加，說明了兩者隨著距離增加而增大的尺度效應
。

The solute transport machanisms of groundwater are caused by
advection,dispersion/diffusion and complex pore geometry.
Mixing mechanisms make the dispersion coefficient be a function
of scale length.This reseasch uses the generalized dispersion
theory which come from the basis of Taylor''s dispersion work.
By choosing self -adjoint operator of eigenfunctions, the
dispersion coefficient of groundwater transport is redefined.
Results of this research suggest that the dispersion
coefficient is a strong function of of the hydraulic
conductivity, and the initial distribution of solute. It
exhibits a transient behavior and will reach a long-time
asymptotic value. The effective soulte velocity has a similar
behavior. This explain why the dispersion coefficient is scale
dependent.