Wave Dissipation over Vegetation
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Info:
Large-scale modelling of waves with spectral wave models such as SWAN is indispensable for design of coastal structures and the assessment of flood risk. The wave dissipation approach works out well for average bathymetries with e.g. sandy material. One of the exceptions is the modelling of wave dissipation due to submerged or emerging aquatic vegetation. Wave dissipation due to vegetation can be represented as bottom friction (implicit modelling) or as an additional disispation function (explicit modelling). The second one assumes that vegetation can be represented as cylinder or plates (canopies) tha can have different properties throught the horizontal and vertical axis. . Wave dissipation over any kind of species has been measured at numerous locations all over the world, providing insight in the physical process and validation material for the various models that have been developed so far. Within the BE-SAFE project, wave measurements over salt marshes in the Dutch Wadden Sea were carried out during several storms. The modelled and measured spectral energy distribution still showed significant and not yet understood differences. Recently Jacobsen et al. (2019) published a new, frequency-dependent dissipation model for waves propagating over a canopy. This is considered as a promising development.
The main objectives of the thesis project are:
1) Understand the processes related to spectral wave dissipation for submerged vegetation
2) Improve the wave vegetation module of SWAN to provide better results on the wave energy spectra for projects.
a. Validate with lab and field data
b. Implement ( Jacobsen et al., 2019 ) in SWAN SWAN_J ) and test it
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