EurOCEAN 2000 - Vlaams Instituut voor de Zee

• the nearshore circulation model SHORECIRC has been applied to study the infragravity
wave response to the bathymetry and shortwave forcing. Specific attention has been paid
to the generation of accurate boundary conditions for the bound incoming long wave.
• a linear model has been developed for the generation of long waves by obliquely incident
grouped short waves on an along-shore uniform beach. Effects of set-up and longshore
currents on the long wave response are taken into account.
• the development of rip channels has been simulated with a 2DH numerical coastal area
model. The results for normal incidence exhibit significant scatter but compare relatively
well with analytical results.
• experiments have been carried out on the circulation current over a longshore bar with a
rip channel. The relation bewtween the water level, the wave conditions and the maximum
velocity in the rip current has been investigated.
• the horizontal exchange of momentum in wave-driven currents and its importance for the
velocity distribution has been invstigated. It is found that wave-current interaction can
play an important role.
• survey data from the test site Rantum, Sylt, North Sea has been finalised, behavioural
trends of morphologic changes, rip currents and current systems have been deducted.
• a simplified linear model for examining bar stability has now been developed. Results
clearly indicate that a barred beach is less stable and will tend to exhibit instability.
• a stability analysis and the investigation into the initial formation of rip channels on a
long, straight and uniform longshore bar has been performed with a numerical modelling
system.
• the Coast3D test site of Egmond has been modelled using a 3D numerical modelling
system.
• a systematic exploration of the linear instability with simple descriptions of sediment
transport in case of oblique incidence has been achieved. Two behaviors are obtained
depending of the
Project 4. Structure-seabed interaction
Goal of this project: This project aims at understanding, modelling and describing the effects of
various coastal structures on the nearshore morphology. The project is divided into two topics:
• modelling of the far field morphological evolution around structures, and
• review of the experience on implementation of coastal structures.
The modelling applied to the role of structures will profit by developments and improvements
carried out in other parts of SASME. The capabilities and limitations of the different modelling
principles for different types of structures are analysed. The model results are used to analyse
the flow, transport pattern and morphological development around the structures, to obtain a
better understanding of the effect of the structures and of how a series of structures interacts.
The aim of the review study is to provide clear guidelines on the use of coastal structure in
coastline protection programmes. These guidelines will be based on a review of existing
experience with structures, and on the results of the detailed modelling of the effects of
structures during the SASME project. The guidelines are recognised as one of the most
important end products of SASME and will be published both in a detailed report and as a
review paper.
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