Coupling DuMuX and DUNE-PDELab to investigate evaporation at the interface between Darcy and Navier-Stokes flow

Grüninger, Christoph; Fetzer, Thomas; Flemisch, Bernd; Helmig, Rainer

doi:10.18419/opus-9360

Cited by 2 publications

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“…DuMu X uses a locally mass-conservative finite-volume scheme and the implicit Euler method for the space and time discretization, respectively. The porous-medium subdomain was discretized by a cell-centered two-point flux scheme and the discretization of the free-flow subdomain was performed by a staggered grid scheme (Marker and Cell scheme, as shown in Figure S1, panels c and d) [51]. Both domains are solved fully monolithically with Newton's method to solve the system of non-linear equations in combination with a direct linear solver (UMFPACK).…”

Section: Numerical Implementationmentioning

confidence: 99%

On multicomponent gas diffusion and coupling concepts for porous media and free flow: a benchmark study

et al. 2021

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Multicomponent gas transport in porous media and at the interface between porous media and free flow occurs in a wide range of technical and environmental systems. Modeling tools are required for the quantitative description of such coupled environmental compartments. We present a benchmark study to compare different diffusion models as well as different coupling concepts employed for the description of multicomponent gas flow and transport at the porous medium/free-flow interface. The benchmark problems allowed us to compare two diffusion models (Fickian and Maxwell-Stefan formulations) for predicting the transport behavior of multicomponent mixtures in porous media and in presence of a free flow. The examples highlighted the importance of interaction between different diffusing components by applying the Maxwell-Stefan formulation, as well as the impact of the free flow velocity on gas migration at the interface under diffusion-and advection-dominated conditions. The problems were solved using two simulation tools, incorporating different coupling concepts to describe the physics of flow and transport processes. In COMSOL Multiphysics, we implemented a single-domain Brinkman approach, whereas in the DuMu X simulator we used a two-domain approach with the Navier-Stokes equation in the free flow and Darcy's law in the porous medium. Also, the formulation of the Maxwell-Stefan equation for multicomponent transport was different between the two codes. Despite the different modeling concepts, mathematical descriptions and numerical schemes implemented in the two simulators, their outcomes demonstrate excellent agreement for all benchmark problems, as well as the capability to reproduce the results of previous modeling and experimental studies.

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Section: Numerical Implementationmentioning

confidence: 99%

On multicomponent gas diffusion and coupling concepts for porous media and free flow: a benchmark study

et al. 2021

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Obstacles, Interfacial Forms, and Turbulence: A Numerical Analysis of Soil–Water Evaporation Across Different Interfaces

et al. 2020

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Exchange processes between a turbulent free flow and a porous media flow are sensitive to the flow dynamics in both flow regimes, as well as to the interface that separates them. Resolving these complex exchange processes across irregular interfaces is key in understanding many natural and engineered systems. With soil-water evaporation as the natural application of interest, the coupled behavior and exchange between flow regimes are investigated numerically, considering a turbulent free flow as well as interfacial forms and obstacles. Interfacial forms and obstacles will alter the flow conditions at the interface, creating flow structures that either enhance or reduce exchange rates based on their velocity conditions and their mixing with the main flow. To evaluate how these interfacial forms change the exchange rates, interfacial conditions are isolated and investigated numerically. First, different flow speeds are compared for a flat surface. Second, a porous obstacle of varied height is introduced at the interface, and the effects the flow structures that develop have on the interface are analyzed. The flow parameters of this obstacle are then varied and the interfacial exchange rates investigated. Next, to evaluate the interaction of flow structures between obstacles, a second obstacle is introduced, separated by a varied distance. Finally, the shape of these obstacles is modified to create different wave forms. Each of these interfacial forms and obstacles is shown to create different flow structures adjacent to the surface which alter the mass, momentum, and energy conditions at the interface. These changes will enhance the exchange rate in locations where higher velocity gradients and more mixing with the main flow develop, but will reduce the exchange rate in locations where low velocity gradients and limited mixing with the main flow occur.

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Coupling DuMuX and DUNE-PDELab to investigate evaporation at the interface between Darcy and Navier-Stokes flow

Cited by 2 publications

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On multicomponent gas diffusion and coupling concepts for porous media and free flow: a benchmark study

On multicomponent gas diffusion and coupling concepts for porous media and free flow: a benchmark study

Obstacles, Interfacial Forms, and Turbulence: A Numerical Analysis of Soil–Water Evaporation Across Different Interfaces

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