Big coastal physical models – controlling variable wave boundaries

In coastal physical modelling, when bathymetries are complex and sea-states vary locally, it becomes necessary to combine all natural features in a single 3D physical model. This leads to physical models requiring long wave generation boundaries over which wave heights and directions could vary significantly. HR Wallingford has developed a novel wave generation method by which the wave height and direction along the paddle can be varied to match target wave parameters along the generation boundary. A recent large physical modelling study of a new port development in Chile, had a wave generation boundary of 5.2 km. The local bathymetry in the model needed to include a deep submarine canyon, which extended several km offshore and reached depths of over 150 m, which lead up to the breakwater of the new port. Due to the canyon, the wave heights along the wave generation boundary varied by 30-40 %. As part of the study, an investigation was carried out to determine the optimal calibration method; whether using variable wave heights and / or variable directions along the paddle front best matched the predicted design conditions at the structure toe. An ARTEMIS numerical model was used as part of the validation and calibration process.