NUMERICAL SIMULATION OF EXTREME EVENTS FROM FOCUSED DIRECTIONALLY SPREAD WAVEFIELDS

摘要

So-called extreme, rogue, or freak waves are currently receiving increased attention within the coastal and offshore engineering communities, as they are thought to be important in the design of ships and offshore structures. In this work we simulate extreme three-dimensional wave events from focused, directionally spread wavefields with a fully-nonlinear, high-order Boussinesq-type model. The simulations are based on recently conducted laboratory experiments, involving waves out to (wavenumber times depth) kh = 13.25. An excellent match in both free surface elevations and vertical velocity profiles is demonstrated. While the accuracy of free surface computations has previously been established with the present method, this work marks the first validation of velocity kinematics directly against experimental measurements, generally confirming previously claimed depth limitations.