The Effect of Sudden Permeability Changes in Porous Media Filling Box Flows

Isolated buoyant convection in a two-layered porous medium with an inclined permeability jump

“…In this fashion, we were able to convert from an average pixel intensity to an average dye concentration and then finally to an average salt concentration and fluid density, dye and salt having been mixed into the source fluid in fixed proportion. An implicit assumption in this latter step is that salt and dye are transported at roughly equal speeds, which is justified given the large Péclet numbers of interest here (Sahu & Flynn 2017). By this procedure, we thereby estimate the average reduced gravities in the upper and lower layers separately.…”

“…As suggested by the name, the run-out length is the horizontal distance at which the volume of fluid supplied to the gravity current is just balanced by that draining from underneath. Whereas the case of a horizontal permeability jump has been studied by Goda & Sato (2011) and Sahu & Flynn (2017), there are numerous geological examples where the permeability jump makes a non-trivial angle to the horizontal. These examples include the Wabamun groups (Bachu et al 2008a) in Western Canada, which are used as repositories for acid gas, the Entrada and Weber formations in the United States Rocky Mountain region (McPherson & Matthews 2013) and China's Shiqianfeng group in the Ordos Basin (Jing et al 2019) all of which are used as repositories for In light of the above examples, it is surprising that more attention has not been paid to the (asymmetric) problem of gravity current propagation along a sloping, permeable boundary.…”

Dispersive entrainment into gravity currents in porous media

“…The experimental images of Huppert et al (2013) and Sahu & Flynn (2017) also show that the gravity current is significantly thicker at the nose even at the laboratory scale than seen in the homogenous cases (see figure 9). This is consistent with our findings shown in figure 4(a) for largert, which is greater in those experiments due to enhanced α.…”

“…For example, gravity currents on an inclined surface have been studied by Vella & Huppert (2006) and Gunn & Woods (2011), or in a vertically confined medium by Nordbotten, Celia & Bachu (2005), MacMinn et al (2012), Pegler, Huppert & Neufeld (2014) and Zheng et al (2015). Moreover, by relaxing the restriction of a homogeneous medium, Pritchard, Woods & Hogg (2001), Goda & Sato (2011) and Sahu & Flynn (2017) have investigated gravity currents in layered porous media of differing permeabilities, while Zheng, Christov & Stone (2014) have investigated flow in horizontally heterogeneous medium. Formulations for modelling gravity currents in a highly heterogeneous medium have been presented by Anderson, McLaughlin & Miller (2003, 2004, who describe homogenization methods for the averaging of medium properties.…”

Buoyancy-driven plumes in a layered porous medium

“…In contrast to these studies of immiscible or laterally spreading fluids, the effect of thin low-permeability or fractured layers on a diffusing plume has not been previously explored. Perhaps the most comparable studies to the present were carried out by Roes et al (2014) and Sahu & Flynn (2017). The former provided a detailed theoretical and experimental study of the dynamics of a descending plume in a porous, confined 'fillingbox' environment, in which the plume could partially drain through the base of the domain as a rough model of a 'leaking' or fractured porous medium.…”