Anomalous transport dependence on Péclet number, porous medium heterogeneity, and a temporally varying velocity field.
Anomalous transport dependence on Péclet number, porous medium heterogeneity, and a temporally varying velocity field.
复制标题
异常输运对佩克莱数、多孔介质异质性和随时间变化的速度场的依赖性。
作者：
A. Nissan;B. Berkowitz
研究了Péclet数（Pe）对惰性化学示踪剂在非均质多孔介质中迁移的影响。我们模拟流体流动和运输通过二维孔隙尺度矩阵具有不同的结构复杂性。随着Pe的增加，由于复杂速度场的影响越来越占主导地位，输运的异常性质随着宿主域变得更加异质而增强。的敏感性（异常）运输到Pe示出控制的介质结构。我们量化Pe的影响，通过解释连续时间随机游走法（CTRW）框架内的数值模拟，并将Pe内的底层示踪剂过渡时间分布。然后，我们调查运输行为受到时间变化的速度场的大小，占示踪剂的传播控制Pe。由于Pe的非线性影响的运输行为，我们表明，在速度场的时间变化可以导致增加的异常性质的运输。
We investigate the effects of the Péclet number (Pe) on transport of an inert chemical tracer in heterogeneous porous media. We simulate fluid flow and transport through two-dimensional pore-scale matrices with varying structural complexity. With increasing Pe, the anomalous nature of the transport becomes enhanced as the host domain becomes more heterogeneous, due to the increasingly dominant effects of the complex velocity field. The sensitivity of (anomalous) transport to Pe is shown to be controlled by the medium structure. We quantify the effects of Pe by interpreting the numerical simulations within the continuous time random walk method (CTRW) framework, and incorporating Pe within the underlying tracer transition time distribution. We then investigate transport behavior subjected to temporal variation in the velocity field magnitude, accounting for tracer propagation controlled by Pe. Because of the nonlinear influence of Pe on the transport behavior, we show that temporal variations in the velocity field can lead to an increase in the anomalous nature of the transport.