Space–time upscaling of reactive transport in porous media

Reactive transport in saturated/unsaturated porous media is numerically upscaled to the space–time scale of a hypothetical measurement through coarse-grained (CGST) averages. The reactive modeled at fine-grained Darcy by actual number molecules involved reactions which undergo advective and diffusive movements described global random walk (GRW) simulations. CGST averages verify identities similar local balance equation allow us derive expressions for flow velocity intrinsic diffusion coefficient terms averaged microscopic quantities. latter are further used CGST-GRW numerical approach. upscaling approach applied biodegradation processes saturated aquifers variably soils compared classical volume One finds that if process characterized slow variations time, as homogeneous reaction systems, differences between two negligible. Instead, significant can be extremely large simulations time-dependent both aquifers.