Full scale CFD validation using ship performance and wave pattern measurements of a mega cruise ship

The shipping industry is directly impacted by the global challenge of reducing greenhouse gas emissions. Improvements can be achieved by hull form optimization when designing new ships. Computational Fluid Dynamics (CFD) is nowadays regularly applied for basic resistance simulations as well as for e.g. self-propulsion with rotating propellers or maneuvering in waves. In order to avoid scale-effects, it is increasingly common to perform ship scale CFD calculations. Unfortunately, the available full scale data that can be used for validation are limited. Specifically, flow velocity and radiated wave pattern data are rare at full scale because of the complexity of performing such measurements.

Nevertheless, in the current work, full scale wave pattern measurement were performed on a 330 meter long cruise ship sailing at 20 knots using the Digital Image Correlation technique. This is an image analysis method capable of measuring deformations of a surface in space. The approximate size of the field of view was 75 m by 30 m. The ship’s speed, shaft power, propeller rate, motions and environmental waves were measured as well. Additionally, Reynolds Averaged Navier-Stokes (RANS) simulations were performed using STARCCM+. The propeller was modelled both as an actuator disk as well as a rotating propeller with a sliding interface. The turbulence closure model was k-ω SST and the free surface was modelled using the Volume of Fluid method. The balance between hull resistance and propeller thrust was verified as a first step, showing less than 4.0% difference. The power determined by CFD was validated against the one measured during the sea trials with less than 3.6% difference. Finally, the comparison of the stern wave pattern resulting from full scale CFD simulations with the pattern measured using DIC showed excellent agreement with good accuracy.