Numerical and experimental assessment of hydrodynamic force of a heaving porous disk

ABSTRACT

The heave disk has been extensively employed as a motion damping device in floating offshore structures and inclusion of porosity on the disk further increases damping by generation of hole vortices. The present study explores the hydrodynamic forces of the solid and porous heave disk through numerical approaches and laboratory experiments. A simplified axisymmetric CFD model based on OpenFoam software is adopted here for numerical calculation. For verification of the numerical model, the laboratory test is conducted with the heave disk for different porosities and KC (Keulegan-Carpenter) numbers. The simplified CFD solutions are in good agreement with experimental results. It is observed that the porous disk with porosities of 0.049 and 0.11 shows maximum damping within the given range of KC numbers. From flow visualisation near porous disk, it is shown that as porosity increases, the increased flow through openings inhibits the formation of edge vortex.

KEYWORDS:

• Heave disk
• CFD
• experiment
• flow visualisation
• damping
• porosity

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was supported by the 2022 scientific promotion programme funded by Jeju National University, South Korea.