Experimental and numerical investigation of wave resonance in moonpools at low forward speed

• Moonpool wave resonance at low forward speed.
• New numerical method combining potential flow and viscous flow.
• Applying harmonic polynomial in cell method and the finite volume method.
• Extensive 2D model test campaign on a moonpool section.

In order to study the behavior of resonant piston-mode resonance in a moonpool at low forward/incoming current speed, we performed a series of experiments and compared them to a nonlinear hybrid method which couples potential and viscous flow. The setting is a 2D box section with a moonpool gap in the middle, forced to oscillate in heave with a given amplitude and frequency, while simultaneously travelling at a given constant forward speed. The numerical method couples a Navier–Stokes (CFD) solver using the Finite Volume Method (FVM), with a potential flow method using the Harmonic Polynomial Cell method (HPC). It is found that the moonpool behavior is slightly reduced with a low forward velocity, and the reduction is dependent on the heave forcing amplitude.