Performance of interFoam on the simulation of progressive waves

ABSTRACT

The performance of interFoam (a widely used solver within OpenFOAM®) in simulating the propagation of a nonlinear (stream function solution) regular wave is investigated in this work. It is demonstrated that over time there is a tendency for surface elevations to increase, wiggles to appear in the free surface, and crest velocities to become (severely) overestimated. It is shown that increasing the temporal and spatial resolution can mitigate these undesirable effects, but that a relatively small Courant number is required and fine discretization is needed, indicating that many past simulations have not converged. It is further demonstrated that discretization schemes and solver settings (often treated as a “black box” by users) can have a major impact on the results. This impact is documented, and it is shown that obtaining a “diffusive balance” is crucial to accurately propagate a surface wave over long distances without requiring exceedingly high temporal and spatial resolutions. Finally, the new code isoAdvector is demonstrated to produce comparably accurate results to interFoam, while maintaining a sharper surface. It is hoped that the present study will raise awareness of potential shortcomings of interFoam and enable a more accurate and optimal use, in CFD simulation of free surface waves.

KEYWORDS:

• InterFoam
• waves
• discretization practises
• isoAdvector

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The first two authors acknowledge support from the European Union project ASTARTE–Assessment, Strategy And Risk Reduction for Tsunamis in Europe, Grant no. 603839 (FP7-ENV-2013.6.4-3). The third author additionally aknowledges: Sapere Aude: DFF–Research Talent grant from The Danish Council for Independent Research | Technology and Production Sciences (Grant-ID: DFF - 1337-00118). The third author also enjoys partial funding through the GTS grant to DHI from the Danish Agency for Science, Technology and Innovation. We would like to express our sincere gratitude for this support.