On the role of uncertainty for the study of wave–structure interaction

• We investigate wave–structure interaction using a wave and structural dynamic model.
• The numerical model is employed to quantify overtopping and displacement.
• Different wave conditions are simulated using Monte Carlo simulations.
• Ensemble estimates and its variability is computed for overtopping and sliding.
• Numerical results suggest the importance of including uncertainty in parameterizations.

We present a methodology to quantify the breakwater failure by means of the partial coupling of a nonlinear wave transformation model and a structural dynamic model. Nonlinear wave transformation is simulated by a two-dimensional VOF-type model (Cornell Breaking Wave and Structures), which solves the Reynolds-averaged Navier–Stokes (RANS) equations with a turbulence closure and a free-surface tracking scheme. The numerical model is used to calculate wave-induced forces and overtopping volume on low mound breakwaters. This information is further employed as the boundary conditions in a structure dynamic model to quantify the structural failure. Simulations over a wide range of wave conditions allow us to investigate the role of both epistemic-type and aleatoric uncertainty on wave-induced sliding and overtopping. Monte Carlo simulations are employed to conduct several realizations for an assessment of the aleatoric uncertainty in the failure prediction. The latter approach allows us to obtain ensemble values and the corresponding (natural) variability of overtopping, lateral forces, and sliding for a given forcing. Moreover, numerical results show that the structure displacement is sensitive to frequency spread values (epistemic uncertainty), whereas wave overtopping is less sensitive to such parameter. This approach can be employed to develop parameterizations that include the aleatoric uncertainty in their prediction.