OpenFOAM® Journal

3D Solver for Viscous Fluids to Simulate Lava Flows

2025-02-18T12:12:27-05:00

In this work, we present a new OpenFOAM solver, called interThermalRadConvFoam, to simulate free-surface viscous fluids with temperature changes due to radiative, convective, and conductive heat exchanges. The solver is based on interFoam (available in OpenFOAM) and thus on the Volume of Fluid technique used to describe the multiphase dynamics of two incompressible, viscous, and immiscible fluids (based on the Interface Capturing strategy). In our model, the two fluids are the fluid of interest with high viscosity and the surrounding atmosphere. Being interested in temperature effects, we added to the mass and momentum equations from interFoam an equation for energy that models the thermal exchanges between the fluid and the environment. Furthermore, a temperature-dependent viscoplastic model is used for the final application to lava flows. Here we present some results of numerical tests performed with interThermalRadConvFoam for a benchmark from literature based on a laboratory experiment and an application to a real lava flow by simulating the Pico do Fogo 2014–2015 Eruption. For the simulation of the laboratory experiment, we also present simulations executed using a dynamic mesh with adaptive refinement.

Development of an OpenFOAM Solver to Investigate the Dynamic Absorption and Desorption Processes in Metal-hydrides

2024-11-29T07:10:33-05:00

The purpose of this paper is to introduce twoRegionHydrideFoam, a newly developed solver that enables the calculation of hydrogen absorption and desorption reactions in metal-hydrides. This solver integrates simulations of chemical, thermodynamic, and continuum mechanical processes. The primary focus is to provide a detailed, locally resolved description of hydrogen loading cycles under varying temperatures and pressures. We discuss the mathematical model assembled for this purpose and its implementation in OpenFOAM. Additionally, precise heat transfer calculations are achieved using the groovyBC third-party library. The performance and accuracy of the solver are demonstrated through a parametric study where key system parameters are systematically varied and analyzed. Furthermore, this paper includes preconfigured example cases to facilitate understanding and application of the solver. This solver meets the increasing demand for advanced tools in sustainable energy storage and hydrogen technology research. By expanding the capabilities of OpenFOAM®, it offers a powerful platform for researchers and engineers to explore and develop innovative solutions within the hydrogen economy.

Analysis of Coupling Strategies for Conjugate Heat Transfer Problems

2024-11-02T15:40:18-04:00

Numerical solutions to conjugate heat transfer (CHT) problems present challenges regarding accuracy, stability, and computational cost. The current study presents a detailed analysis of the existing OpenFOAM® CHT solvers, including commentary on the multiple forms of the available governing equations and coupling methods. Subsequently, two modified CHT approaches are proposed: (i) a new partitioned algorithm with improved efficiency, and (ii) the available monolithic CHT solver in foam-extend-4.0 was modified and extended to multiple regions. The performance of the proposed solvers is assessed on several transient test cases with various degrees of coupling strength. The results reveal the superiority of the proposed monolithic approach over the partitioned ones, particularly for problems for more than two regions. It is also found that the new partitioned approach is computationally more efficient than the available partitioned solvers.

An Open-Source Framework for Modeling the Evolution of Fiber Orientation

2024-01-11T10:48:36-05:00

Modeling fiber orientation plays a crucial rule in predicting the behaviour of fiber reinforced thermoplastic materials. The equation that governs the evolution of the fiber orientation is hyperbolic in nature and requires handling fourth-order tensors, which are currently unavailable in OpenFOAM® .
The current work explores the possibility of using OpenFOAM® and symbolic computation for modeling the evolution of fiber orientation. For this purpose, a functionObject was programmed to work as a plug-in solver for any OpenFOAM® incompressible flow solver, with the ability to compute the evolution of the second-order orientation tensor in a decoupled manner. Several fiber orientation models and closure relations available in the literature were implemented in the tool, which were verified by comparing their predictions with independent results obtained by numerically integrating the associated governing equations.

Modelling Thermo-Electrohydrodynamic Convection in Rotating Spherical Shell Using OpenFOAM®

2024-10-01T11:39:11-04:00

Convection in rotating spherical shells can be considered a simplified analogue of many geophysical and astrophysical flows. Here, we investigate a direct numerical simulation of a dielectric fluid in an electric central force field inducing thermo-electrohydrodynamic (TEHD) convection with numerical methods to obtain an accurate solution of the transport equations describing rotating TEHD convection in a non-isothermally heated spherical shell. The choice of the numerical model is based on the International Space Station Experiment GeoFlow and its successor, AtmoFlow. The numerical methods consist of a custom-developed finite volume solver based on the OpenFOAM ecosystem that is not limited to any geometric restrictions, a commercially developed finite element method, and a pseudo-spectral method. This study aims to validate a custom-coded finite volume solver for investigating TEHD convection for a parametric study of the AtmoFlow spherical shell experiment. The developed TEHD finite volume solver showed solution errors of 1% or less compared to the other two implemented numerical methods.

Temporary Cover 2025

2025-04-29T12:54:09-04:00

Title: Hydraulic design of natural flows for enhanced biodiversity using OpenFOAM

Author:

Eric Lillberg

Vattenfall AB, Research & Development

SE-169 92 Stockholm, Sweden

Visit: Evenemangsgatan 13

https://orcid.org/0009-0004-8256-7517

Testing Strategies for OpenFOAM Projects

2025-02-11T14:32:30-05:00

While testing is increasingly recognized as essential in scientific software development, it is not yet standard practice within the OpenFOAM community for developing new solvers and features. This gap stems partly from the challenges of integrating testing into typical OpenFOAM workflows and limited guidance on implementing effective tests. Writing tests for complex software like OpenFOAM based projects presents unique obstacles, including difficulty in configuring tests for various cases. This paper addresses these issues by discussing established test types in the context of OpenFOAM, identifying common challenges in developing tests for this platform, and suggesting best practices to enhance the testability of code based on OpenFOAM. Detailed guidance is provided for integrating the Catch2 unit test framework, alongside two new tools: the foamUT framework and the OpenFOAM Benchmark Runner (OBR), which facilitate unit and integration testing. To illustrate these tools in practice, we present three case studies. The first demonstrates the direct integration of Catch2 in the WENOExt project, showcasing test case creation and its synergy with OpenFOAM projects. The second introduces the foamUT framework, which simplifies Catch2 integration for OpenFOAM projects. Finally, the OBR framework is used for benchmarking and integration tests in the OpenFOAM Ginkgo layer. Additionally, we discuss the current state of testing in OpenFOAM and emphasize the need for more comprehensive testing practices within this community, particularly with libraries such as Catch2. Overall, this paper serves as a practical introduction to unit and integration testing for OpenFOAM developers and introduces new tools that lower the barrier to entry, improve test suite robustness, and simplify unit test integration.