Investigating the dependencies of individual overtopping volumes on vertical wall breakwaters under non-breaking waves

Wave overtopping of coastal structures is generally expressed in terms of average discharge and maximum overtopping volume. While substantial research can be found on the relationship of such variables with incident spectral characteristics and other geometrical dimensions, limited research has been done to identify the conditions for which...

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....

An efficient numerical approach to model wave overtopping of rubble mound breakwaters

Worldwide, rubble mound breakwaters are designed and built to shelter and protect coastal areas from overtopping and flooding, especially harbours and shorelines. Rubble mound breakwaters are essential to preserve desired hydraulic conditions within the hinterland, avoiding damage to inhabited or industrial areas. This research focuses on the...

Long waves in the North Sea: Distribution, generation and measurement methods

This report presents the results of a research concerning long waves in the North Sea. ‘Long waves’ in this research is a collective name for various types of waves that are longer than the well-known sea-swell waves, here referred to as ‘short waves’. Wave types that are referred to as long waves are infragravity waves, meteo-tsunami’s, seiches...

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...

Analysis of Spectra, Wave Grouping and Long Wave Phenomena of Real Measured Waves in Coastal Waters

Real coastal waves measured at 4 different locations in the world were analyzed in detail. Long travelled swell measured in the Pacific coast of Costa Rica, wind swell from the Atlantic coast of Costa Rica, short period wind waves from the Ebro Delta in Mediterranean coast of Spain, and waves measured during the passing of Hurricane Wilma near...

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...

Swell and wave-groups at Saldanha bay

Mooring problems are one of the most important issues in port construction and port operation when harbours are facing the open sea. Operational standards usually define that cargo handling for large vessels is possible when significant wave height is below some level, i.e., 0.5 [m]. However, several ports have reported mooring problems when the...

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...

Long wave generation and behavior on a plane sloping beach

This thesis studies the relation between short wave groups and long wave motion in the shore-normal case on a uniformly sloping bottom. The short wave groups can be described through two time scales; the time scale of the individual waves and the time scale of the groups. The energy of the individual waves is dissipated through wave breaking and...

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...