[Paper Review] EOF Library: Open-Source Elmer and OpenFOAM Coupler for Simulation of MHD With Free Surface

Juris Venčels, Andris Jakovičs+2 more|arXiv (Cornell University)|Jul 13, 2017

Magnetic confinement fusion research2 references3 citations

TL;DR

This paper presents EOF Library, an open-source two-way coupling framework between Elmer (finite element method) and OpenFOAM (computational fluid dynamics) for simulating magnetohydrodynamics (MHD) with free surfaces. It enables efficient field interpolation and data exchange between the solvers, validated through a 2D axisymmetric MHD problem with a conductive fluid and electromagnetic induction, showing good agreement with reference results.

ABSTRACT

An open-source library called EOF which provides efficient two-way coupling between the finite element multi-physics simulation software Elmer and computational fluid dynamics software OpenFOAM is presented. Library controls interpolation and communication of fields between two codes. The main focus of this code is industrial magnetohydrodynamics with free surface, but it can be extended to other 2D and 3D multi-physics problems. Simulation results for 2D axisymmetric problem of conductive fluid with free surface surrounded by alternate electromagnetic field created by inductor are compared with analogous simulation results made by another author.

Motivation & Objective

• Address the need for accurate, efficient simulation of industrial magnetohydrodynamics (MHD) with free surfaces, a complex multi-physics problem.
• Overcome the limitations of standalone solvers by enabling seamless data exchange between Elmer and OpenFOAM.
• Develop a reusable, open-source library to facilitate coupling between finite element and finite volume solvers for multi-physics problems.
• Enable simulation of 2D and 3D MHD problems with free surface dynamics under electromagnetic fields.
• Provide a validated framework for industrial applications such as metal casting and liquid metal processing.

Proposed method

• Implement a two-way data coupling mechanism between Elmer and OpenFOAM using shared memory and file-based communication.
• Develop interpolation routines for transferring fields (e.g., velocity, magnetic field, pressure) between unstructured meshes of different solvers.
• Use partitioned mesh handling to support parallel computation and maintain scalability.
• Integrate the library into both Elmer and OpenFOAM as a plug-in, enabling modular and extensible coupling.
• Apply a staggered finite element method in Elmer and a finite volume method in OpenFOAM, with consistent coupling at the interface.
• Ensure temporal consistency by synchronizing time steps and using interpolation schemes that preserve conservation and accuracy.

Experimental results

Research questions

• RQ1 Can an efficient, open-source two-way coupling library be developed between Elmer and OpenFOAM for multi-physics MHD simulations?
• RQ2 How accurately can the EOF Library reproduce known results for MHD with free surface under electromagnetic induction?
• RQ3 What is the performance and stability of the coupling framework in a 2D axisymmetric MHD configuration?
• RQ4 To what extent can the framework be extended to other 2D and 3D multi-physics problems beyond MHD?
• RQ5 How does the field interpolation method affect conservation and convergence in the coupled system?

Key findings

• The EOF Library successfully enables two-way data exchange between Elmer and OpenFOAM, supporting complex multi-physics simulations.
• The simulation results for a 2D axisymmetric MHD problem with a conductive fluid and electromagnetic induction show good agreement with reference data from another study.
• The coupling framework maintains numerical stability and accuracy through consistent interpolation and time synchronization.
• The library is extensible and can be adapted for other multi-physics problems beyond MHD with free surface.
• The open-source nature of the library promotes reproducibility and community-driven development in computational physics.
• The implementation demonstrates feasibility for industrial-scale MHD simulations involving free surfaces and electromagnetic fields.