31 May 2021 to 4 June 2021
Europe/Berlin timezone

Benchmark of different coupling schemes for reactive transport in saturated porous media

1 Jun 2021, 15:10
15m
Oral Presentation (MS7) Mathematical and numerical methods for multi-scale multi-physics, nonlinear coupled processes MS7

Speaker

Dr Vanessa Montoya (Helmholtz Centre for Environmental Research (UFZ) Department of Environmental Informatics (ENVINF))

Description

The development of continuum reactive transport models in porous media traces back to mid-80’s when the theoretical framework to consider reactions in mass transport equations was outlined. Since their establishment, the operator-splitting (OS) approach has been frequently used due to its easy implementation and computational efficiency in large scale simulations including complex chemical processes. Existing and widely used OS-finite element framework in reactive transport normally adopts different collocation schemes for spatially discretizing the transport (i.e. advection and diffusion) and the reaction term of the advection-diffusion-reaction equation. While this numerical approach in general works well in homogeneous systems, it may fail if the field variables (i.e. concentration, hydraulic pressure) vary rapidly, for example, close to the domain boundaries or in the interfaces between different materials. In these cases sharp gradients exist and standard numerical schemes normally lead to inaccurate and unstable numerical results.
A novel OS-finite element framework adopting a consistent collocation scheme of all the field variables in the integration points has been recently developed in our group, validated and implemented in OpenGeoSys-6 (Lu et al. (2021). Contrary to previous finite element OS-schemes, the reaction term was calculated at the integration point level, instead of the nodes where a chemical solver (i.e. Phreeqc) was called for the chemical speciation calculation. Verification of the new implementation was done by comparing the results with different analytical solutions including a first order bio-degradation reaction and a coupled transport-dissolution processes and feedback on porosity changes. In this study, we extend the validation of the method by benchmarking different numerical coupling schemes and comparing the results to experimental observations obtained in a) a well-controlled laboratory scale column experiment including a dissolution reaction with feedback on porosity changes and b) through diffusion experiments of sorbing cations in clay.

References

Lu et al. (2021) Water Resources Research (submitted)

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Primary authors

Dr Vanessa Montoya (Helmholtz Centre for Environmental Research (UFZ) Department of Environmental Informatics (ENVINF)) Dr Renchao Lu (Helmholtz Centre for Environmental Research (UFZ) Department of Environmental Informatics (ENVINF)) Dr Jaime Garibay-Rodriguez (Helmholtz Centre for Environmental Research (UFZ) Department of Environmental Informatics (ENVINF)) Thomas Nagel (Technische Universität Bergakademie Freiberg) Dr Dmitri Naumov (TU Bergakademie Freiberg) Prof. Haibing Shao (Helmholtz Centre for Environmental Research - UFZ) Olaf Kolditz (Helmholtz Centre for Environmental Research UFZ / TU Dresden)

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