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Roll damping simulations of an offshore heavy lift DP3 installation vessel using OpenFOAM

Floating structures are prominently present in coastal and offshore regions, e.g. ships, pontoons, barges and pipelines. Innovative structures such as wave energy converters and complex wind turbine foundations are currently being installed for renewable energy production. These structures need special installation vessels such as a heavy lift jack-up vessel or a heavy lift floating installation vessel. The workability of these vessels depends on the wave, current and wind loading. Not only the forcing is of large importance for the installation of structures or the transport towards the project location, but also the response to the environmental loads needs an accurate quantification. One of the challenges is to predict is the roll damping behaviour of an offshore installation vessel accurately.

In this work, the roll damping behavior of the offshore heavy lift DP3 installation vessel Orion from the DEME group is studied. Boundary element codes using potential flow theory require a roll damping coefficient to account for viscous effects. In this work, the roll damping coefficient is calculated using the Computational Fluid Dynamics (CFD) toolbox OpenFOAM. The two-phase Navier-Stokes fluid solver is coupled with a motion solver using a partitioned fluid-structure interaction algorithm. The roll damping is assessed by the Harmonic Excited Roll Motion (HERM) technique. An oscillating external moment is applied on the hull and the roll motion is tracked. Various amplitudes and frequencies of the external moment and different forward speeds, are numerically simulated. These high-fidelity full-scale simulations result in better estimations of roll damping coefficients for various conditions in order to enhance the accuracy of efficient boundary element codes for wave-current-structure interactions simulations.