To realise the full potential of Computational Fluid Dynamics (CFD) within ma-
rine science and engineering, there is a need for continuous maturing as well as
verification and validation of the numerical methods used for free surface and interfacial flows.
One of the distinguishing features here is the existence of a water surface undergoing large
deformations and topological changes during transient simulations e.g. of a breaking
wave hitting an off- shore structure. To date, the most successful method for advecting the
water surface in marine applications is the Volume-of-Fluid (VOF) method. While VOF methods have
become quite advanced and accurate on structured meshes, there is still room for improvement when
it comes to unstructured meshes of the type needed to simulate flows in and around complex
geometric structures. We have recently developed a new geometric VOF algorithm called isoAdvector
for general meshes and implemented it in the OpenFOAM interfacial flow solver called interFoam. We
have previously shown the advantages of isoAdvector for simple pure advection test cases on
various mesh types. Here we test the effect of replacing the existing interface
advection method in interFoam, based on MULES limited interface compression, with the
new isoAd- vector method. Our test case is a steady 2D stream function wave propagating in a
periodic domain. Based on a series of simulations with different numerical settings, we conclude
that the introduction of isoAdvector has a significant effect on wave propagation with interFoam.
There are several criteria of success: Preservation of water volume, of interface sharpness and
shape, of crest kinematics and celerity, not to mention computational efficiency. We demonstrate
how isoAdvector can improve on many of these parameters, but also that the success depends on the
solver setup. Thus, we cautiously conclude that isoAdvector is a viable alternative to MULES when
set up correctly, especially when interface sharpness, interface smoothness and calcula- tion
times are important. There is, however, still potential for improvement in the coupling of
isoAdvector with interFoam’s PISO based pressure-velocity solution algorithm.
