Mesh motion is of key importance in assuring adequate CFD modelling of wave-
structure interaction problems, such as wave impact on floating offshore wind turbines
and seakeeping of ships. Wave forcing often leads to large displacements of floating structures.
As a consequence, the fluid domain boundaries need to move in order to accommodate for these
wave-induced displacements. The mesh quality needs to be preserved at all times to guarantee
accurate and stable results for the rigid body displacements as well as for the fluid variables.
Mesh deformation techniques, in particular algebraic mesh motion methods, have been widely used
within the OpenFOAM framework during the last decade. Unfortunately, stability is easily
jeopardized in case of large displacements. Large mesh deformation gives rise to computation- ally
demanding and unstable results. Sliding meshes have been used to address this issue, but they are
cumbersome for multi-degree of freedom motion. Therefore, overset methods have been implemented in
recent versions of OpenFOAM. Especially, the newly implemented overset meth- ods in the OpenFOAM
branch foam-extend, have shown to give good results for an acceptable runtime.
Simultaneously, considerable progress has been made on the development of alternatives for alge-
braic volume-of-fluid methods for free surface modelling, which notoriously suffer from smearing
effects. Although it seems reasonable to expect that the choice in free surface model combined
with a certain mesh motion technique will have an influence on the overal result, the interde-
pendency between mesh motion techniques and free surface modelling has not been studied yet. This
paper aims at taking the first steps towards a better understanding of this mesh motion-free
surface interdependency and, as such, facilitate an informed choice
