This article proposes some possible changes that we are considering, to the way OrcaFlex treats the water inside a hollow spar buoy, i.e. where a spar buoy object in an OrcaFlex model has a non-zero ID specified for one or more of its cylinders. We would welcome feedback from OrcaFlex users (and potential users) on whether the change that we are considering would be a useful.
The existing OrcaFlex treatment of hollow spar buoys is aimed at modelling hollow axi-symmetric structures that flood and drain very freely in the axial direction. But it is less suitable for hollow objects that do not flood and drain so easily, and these proposals aim to address this.