# 2nd International Conference on Simulation Technology

26-28 March 2018
Stuttgart, Germany
Europe/Berlin timezone

## Multi-phase and Multy-physics Modelling

### Monday, 26 March 2018

2:00pm - 3:30pm

Campus Stuttgart-Vaihingen, Pfaffenwaldring 7

Room 7.01

### Hybrid Finite Volume Schemes for Sedimentary Basin simulation in complex settings

Isabelle Faille

Basin simulation aims at reconstructing the evolution through geological time of the porous sedimentary layers and the fluid that fill in. In complex tectonic settings, it needs to account for faults that become a major element of basin evolution. At basin scale, faults are mainly slip surfaces but also zones of deformed rocks that can have a major impact on fluid flow pathways. We present a modeling approach in which a basin is represented by an evolving unstructured mesh that follows sedimentary layers’ deformation. Faults are handled as pairs of internal boundaries across which the mesh is non-matching and that can therefore slide one past the other. Mass and heat transfer are computed using the Hybrid Finite Volume Scheme able to handle properly the deformed and non matching grids. We illustrate how this scheme can be associated to a double layer interface fault model to simulate fluid flow within the fault zone and account for the different fault behaviors.

### A domain decomposition method to couple nonisothermal compositional gas liquid Darcy and free gas flows

Roland Masson Unice, Université de Nice Sophia-Antipolis

A domain decomposition algorithm is introduced to couple nonisothermal compositional gas liquid Darcy and free gas flow and transport. At each time step, our algorithm solves iteratively the nonlinear system coupling the nonisothermal compositional Darcy flow in the porous medium, the RANS gas flow in the free-flow domain, and the transport of the species and of energy in the free-flow domain. In order to speed up the convergence of the algorithm, the transmission conditions at the interface are replaced by Robin type boundary conditions. The Robin coefficients are obtained from a diagonal approximation of the Dirichlet to Neumann operator related to a simplified model in the neighbouring subdomain. The efficiency of our domain decomposition algorithm is assessed on several test cases focusing on the modeling of the mass and energy exchanges at the interface between the geological formation and the ventilation galleries of geological radioactive waste disposal.





### High order ADER schemes for a symmetric hyperbolic model of compressible two-phase flows

Michael Dumbser

In this talk we present preliminary results obtained with high order ADER discontinuous Galerkin and finite volume schemes for a new class of symmetric hyperbolic models for compressible two-phase flows recently developed by E. Romenski. The governing PDE are a multi-material extension of the unified Godunov-Peshkov-Romenski model of continuum mechanics that is able to describe fluid mechanics and solid mechanics within one single set of governing equations. We show results for one-dimensional test problems in order to validate the mathematical model and the employed numerical techniques.

### Nonlinear finite-volume schemes for complex flow processes and challenging grids

Martin Schneider

The numerical simulation of subsurface processes requires efficient and robust methods due to the large scales and the complex geometries involved. To resolve such complex geometries, corner-point grids are the industry standard to spatially discretize geological formations. Such grids include non-planar, non-matching and degenerated faces. The standard scheme used in industrial codes is the cell-centered finite-volume scheme with two-point flux (TPFA) approximation, an efficient scheme that produces unconditionally monotone solutions. However, large errors in face fluxes are introduced on unstructured grids. The authors present a nonlinear finite-volume scheme applicable to corner-point grids, which maintains the monotonicity property, but has superior qualities with respect to face-flux accuracy. The scheme is compared to linear ones for complex flow simulations in realistic geological formations.

### A Hybrid DSMC/Navier-Stokes Framework to Solve the Coupled Channel Flow and Rarefied Porous Media Flow

Guang Yang

Coupled channel and porous media flow has been a topic of extensive interest for decades. However, the current models and theories are mainly applicable for low speed, in-compressible, and continuum flows. In many emerging technologies, for example, transpiration cooling, the gas flow in the porous media can be rarefied, as the length scale of the pore size may be down to micro- or nanometer. For fluid flow in the transition and free molecular regimes (Kn > 0.1), the continuum hypothesis is no longer applicable. However, the flow in the bulk of the channel is still in the continuum regime, which can be described by the Navier-Stokes equations. In the present study, a hybrid DSMC/Navier-Stokes computational framework is developed in OpenFOAM to solve the coupled system. A direct simulation Monte Carlo (DSMC) method is used for the rarefied porous media flow and the Navier Stokes equations for compressible flow are solved for the channel flow. The momentum and heat transport characteristics at the interface are investigated in detail. The accuracy and efficiency of the present method have also been evaluated.

Postertrack contributions:

Jan Giesselmann (PP5.086); Markus Köppel (PP5.088); Corrado Sotgiu (PP5.100); Alexander Straub (PP5.107); Lukas Eurich & Shahla Shahmoradi & Arndt Wagner & Wolfgang Ehlers (PP5.108); Birane Kane (PP5.114); Julian Valentin (PP5.117); Dominik Wittwar (PP5.120); Serena Vangelatos & Claus-Dieter Munz (PP5.121); David Seus (PP5.124).

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