Assessment of Parametric Rolling Using Coupled Numerical, CFD and Experimental Approaches

This study investigates parametric rolling of a container vessel in regular head waves using a hierarchical modelling framework combining a nonlinear time domain motion solver, a blended Ikeda-based roll damping module, and high-fidelity CFD simulations employing single-mesh and overset mesh strategies. The selected case corresponds to the classical resonance regime for first order parametric instability. All numerical approaches consistently reproduce the fundamental resonance mechanism, including the characteristic frequency relationship between pitch and roll and the exponential growth phase. A key result is the close agreement in instability onset time among the reduced order model and both CFD configurations, demonstrating robust capture of the excitation/restoring interaction governing parametric resonance. Experimental measurements exhibit an earlier visible onset, attributed to unavoidable perturbations and slight irregularities in the basin wave record, highlighting the sensitivity of parametric instability to initial disturbance levels. Differences in saturation amplitude are primarily associated with viscous dissipation modelling and nonlinear free surface phenomena, including green-water events observed experimentally but intentionally excluded from the present CFD setup. The results confirm that accurate representation of the resonance mechanism is achievable across modelling levels, while amplitude prediction remains sensitive to nonlinear damping and deck interaction effects. The developed framework provides a validated and computationally efficient basis for further investigations of damping thresholds, irregular wave excitation, green-water modelling, and coupled propulsion–roll interaction.