Mean travel time of conservative solutes in randomly heterogeneous unbounded domains under mean uniform flow
Mean travel time of conservative solutes in randomly heterogeneous unbounded domains under mean uniform flow
复制标题
平均均匀流下随机异质无界域中保守溶质的平均传播时间
DOI：
10.1029/2002wr001811
复制
发表时间：
2003
影响因子：
5.4
通讯作者：
M. De Simoni
中科院分区：
文献类型：
--
作者：
A. Guadagnini;X. Sanchez‐Vila;M. Riva;M. De Simoni
我们推导了保守溶质在无限静止场内平均流条件下均匀迁移的平均行程时间的封闭式表达式，与导水率的自然对数具有简单的指数相关性。我们的表达式是根据 Guadagnini 等人的二维随机非均匀流中保守溶质的行程时刻和轨迹方程的 σY（对数水力传导率的标准差）的一致二阶展开式发展而来的。 [2001]。因此，它对于 σY2 < 1 的中度异质场名义上是有效的。它对于较大异质度的有效性通过数值蒙特卡罗模拟进行了测试。我们的结果阐明了文献中通过数值观察（并根据经验建模）观察到的平均旅行时间相对于距离的非线性效应。
We derive a closed‐form expression for mean travel time of a conservative solute migrating under uniform in the mean flow conditions within an infinite stationary field with simple exponential correlation of the natural logarithm of hydraulic conductivity. Our expression is developed from a consistent second‐order expansion in σY (standard deviation of the log hydraulic conductivity) of the equations for moments of travel time and trajectories of conservative solutes in two‐dimensional randomly nonuniform flows of Guadagnini et al. [2001]. As such, it is nominally valid for moderately heterogeneous fields, with σY2 < 1. Its validity for larger heterogeneity degrees is tested against numerical Monte Carlo simulations. Our results clarify the nonlinear effect in the mean travel time with respect to distance that has been observed numerically (and modeled empirically) in the literature.