Hanchuan Wu is doctoral researcher at the Department of Hydromechanics and Modelling of Hydrosystems and member of the research training group integrated in SFB 1313 "Interface-Driven Multi-Field Processes in Porous Media". On Tuesday, 27th June 2023 at 17:00 pm, he will give his milestone-presentation.
Date: Tuesday, 27th June 2023
Time: 17:00 pm CET
Title: "Modeling of flow and transport processes in coupled systems involving porous media – Network structure, and coupled compartment"
Place: Pfaffenwaldring 61, U1.003 (MML)
Abstract
For the simulation of various complex applications involving flow and transport in porous media, fully-resolved three dimensional simulations are often computational too demanding. Model reduction methods are therefore often employed yielding lower-dimensional simplified models such as one dimensional networks, which are the focus of this work. Such network structures can effectively reduce computational costs, but the physical and geometrical reduction of the original system often introduces new challenges. In this study, two such model reduction examples, see, are analyzed.
The first example involves the use of an embedded network for modeling exchange processes with the surrounding bulk domain. Corresponding applications include blood vessels in body tissues, root systems, or geothermal wells in the subsurface. For instance, when simulating the water uptake process of a root system embedded in the soil, a key interest lies in the amount of water that roots can uptake from the soil. The use of network structure simplifies the root system into line segments, which leads to a strong increase in efficiency but at the same time also introduces singularities in the solution when mass exchange is modeled by line sources.
Coupled systems of free ow adjacent to a porous-medium appear ubiquitously in nature and in technical applications. The central feature is a pore-network mode (PNM), another example for an embedded network, representing the transition region between the porous matrix and the free flow. This model locally resolves pore-scale processes on a simplied yet equivalent porous geometry which makes it comparatively efficient. Following a monolithic coupling approach, the flows of mass, momentum and energy are implicitly across the domain interfaces must be implicitly preserved without the need for iterations of the coupling. In order to describe the coupled multiphase flow and transport processes in the porous medium with a PNM, the constitutive laws must be numerically modeled in such a way that they still meet all physical challenges in an implicit time discretization.
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