Free thermal convection in heterogeneous porous media

Nguyen, Van Tam; Graf, Thomas; Morel, Carlos R. Guevara

doi:10.1016/j.geothermics.2016.05.006

Cited by 10 publications

(5 citation statements)

References 45 publications

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“…They also found that structured heterogeneity allows instabilities to propagate at a modest combination of fracture aperture and separation distances, while disordered heterogeneity tends to dissipate convection through dispersive mixing. [24] evaluated free thermal convection in randomly heterogeneous media.…”

Section: Introductionmentioning

confidence: 99%

Impact of Low- or High-Permeability Inclusion on Free Convection in a Porous Medium

Yan

Yang

et al. 2019

Geofluids

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Density-driven free convection in porous media is highly affected by large-scale heterogeneity, typical of which are low- or high-permeability inclusions imbedded in homogeneous porous media. In this research, we applied the modified Elder problem to investigate the impact of low- or high-permeability inclusions on the migration of a dense, unstable salt plume. Sensitivity analyses were conducted in terms of the permeability contrast, the effective area (the area of the inclusion beneath the source zone), and the distance of the inclusion from the source zone, all of which were found to play a significant role in controlling the total mass flux released from the source into the media. Results show that (1) a high-permeability inclusion has stronger effects than low-permeability inclusion, due to significantly unbalanced solute distributions caused by accelerated solute transport, (2) the inclusion with a larger effective area has more potential to influence free convection, (3) free convection is more sensitive to the low-/high-permeability inclusion vertically closer to the source zone, and (4) free convection is more susceptible to the low-permeability inclusion horizontally closer to the source zone. For high-permeability inclusions, the inclusion horizontally closer to the source zone influences the transport process more significantly at the early stage, and conversely, the inclusion far from the source zone has a later impact. The results obtained could offer significant implications for understanding unstable density-driven flow and solute transport in porous media with structured heterogeneity.

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Section: Introductionmentioning

confidence: 99%

Impact of Low- or High-Permeability Inclusion on Free Convection in a Porous Medium

Yan

Yang

et al. 2019

Geofluids

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“…It was found that, near the leading edge, the flow is enhanced and the rate of heat transfer is much higher than in the uniform permeability case. The effect of spatial discretization and different types of heterogeneous hydraulic conductivity fields on free thermal convection was examined by Nguyen, Graf & Guevara Morel (2016). The global sensitivity analysis and uncertainty quantification were used to study natural convection in heterogeneous porous media, including velocity-dependent dispersion by Fajraoui et al (2017).…”

Section: Introductionmentioning

confidence: 99%

Gill's stability problem may be unstable with horizontal heterogeneity in permeability

Shankar

Shivakumara

2022

J. Fluid Mech.

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The linear stability of thermal buoyant flow in a fluid-saturated vertical porous slab is studied under the assumption of weak and strong horizontal heterogeneities of the permeability. The two end vertical isothermal boundaries are impermeable and some paradigmatic cases of linear, quadratic and exponential heterogeneity models are deliberated. The stability/instability of the basic flow is examined by carrying out a numerical solution of the governing equations for the disturbances as Gill's proof (A.E. Gill, J. Fluid Mech, vol. 35, 1969, pp. 545–547) of linear stability is found to be ineffective. The possibilities of base flow becoming unstable due to heterogeneity in permeability are recognized, in contrast to Gill's stability problem. The neutral stability curves are presented and the critical Darcy–Rayleigh number for the onset of convective instability is computed for different values of the variable permeability constant. The similarities and differences between different heterogeneity models on the stability of fluid flow are clearly discerned.

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“…Impacts of heterogeneity on the onset of NC under local non-equilibrium conditions have been studied in Nield and Kuznetsov [2015]. Nguyen et al [2016] studied the effects of heterogeneity on fingering phenomena induced by unstable NC. The influence of heterogeneity on stable configuration of NC (horizontal density gradient) has been the subject of several studies.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional natural convection, entropy generation and mixing in heterogeneous porous medium

Yang

Shao

Hoteit

et al. 2021

Advances in Water Resources

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Free thermal convection in heterogeneous porous media

Cited by 10 publications

References 45 publications

Impact of Low- or High-Permeability Inclusion on Free Convection in a Porous Medium

Impact of Low- or High-Permeability Inclusion on Free Convection in a Porous Medium

Gill's stability problem may be unstable with horizontal heterogeneity in permeability

Three-dimensional natural convection, entropy generation and mixing in heterogeneous porous medium

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