Generating an ensemble of mutually exclusive and exhaustive waves targeted for extreme responses

To examine the reliability or performance of marine systems related to dynamic time-varying responses, time domain simulation may be required. But for long durations, brute-force simulation is clearly not feasible from a computational point of view to examine converged extreme value statistics. An additional challenge is defining a set of...

Correct generation of the bound set-down for surface gravity wave groups in laboratory experiments of intermediate to shallow depth

Using linear (first-order) wave generation theory in laboratory experiments, leads to significant contamination of the wave field by free non-linear (second-order) error waves, increasingly so at shallower depths. Second-order wave generation theory has previously been established, and so has correct generation of the bound set-down, made up...

MNLS simulations of surface wave groups with directional spreading in deep and finite depth waters

We simulate focusing surface gravity wave groups with directional spreading using the modified nonlinear Schrödinger (MNLS) equation and compare the results with a fully-nonlinear potential flow code, OceanWave3D. We alter the direction and characteristic wavenumber of the MNLS carrier wave, to assess the impact on the simulation results....

On the initiation of nearshore morphological rhythmicity

Nearshore rhythmicity is often initiated in the period just after a storm where the subtidal bar is turned alongshore uniform. The initiation time as well as the length scales of the created rhythmicity varies from one storm period to another. Here we show that the post-storm wave conditions are related to the initiation of the morphological...

Modeling of very low frequency motions during RIPEX

Numerical computations are used to explain the presence of very low frequency motions (VLFs), with frequencies less than 0.004 Hz, in the rip current velocity signals observed during the Rip-current field Experiment (RIPEX) field experiment. Observations show that the VLF motions are most intense within the surfzone and then quickly taper off in...

Characteristics of phase-averaged equations for modulated wave groups

The project concerns the influence of long waves on coastal morphology. The modelling of the combined motion of the long waves and short waves in the horizontal plane is done by phase-averaging over the short wave motion and using intra-wave modelling for the long waves, see e.g. Roelvink (1993). The evolution of the long-wave motion and the...

Bragg Reflection of Infragravity Waves by Sandbars

Using a multiple-scale perturbation method we derive a set of governing equations describing the transformation of long wave and short wave components in a wave group. These equations are derived from Boussinesq equations with the assumption that the length scale of wave group modulation is in the same order of magnitude as that of the bottom...