Nissan Alon, Berkowitz Brian
Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel.
Phys Rev E. 2019 Mar;99(3-1):033108. doi: 10.1103/PhysRevE.99.033108.
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.
我们研究了佩克莱数（Pe）对惰性化学示踪剂在非均质多孔介质中输运的影响。我们模拟了流体通过具有不同结构复杂性的二维孔隙尺度矩阵的流动和输运。随着佩克莱数的增加，由于复杂速度场的影响日益显著，当主体区域变得更加非均质时，输运的反常性质会增强。结果表明，（反常）输运对佩克莱数的敏感性受介质结构控制。我们通过在连续时间随机游走方法（CTRW）框架内解释数值模拟，并将佩克莱数纳入潜在的示踪剂跃迁时间分布，来量化佩克莱数的影响。然后，我们研究了速度场大小随时间变化时的输运行为，考虑了由佩克莱数控制的示踪剂传播。由于佩克莱数对输运行为的非线性影响，我们表明速度场的时间变化会导致输运反常性质的增加。
