Title
A study of the non-linear properties and wave generation of the multi-layer non-hydrostatic wave model SWASH
Author
Vasarmidis, Panagiotis (Universiteit Gent)
Klonaris, Georgios (Universiteit Gent)
Zijlema, Marcel (TU Delft Environmental Fluid Mechanics) 
Stratigaki, Vasiliki (Universiteit Gent)
Troch, Peter (Universiteit Gent)
Date
2024
Abstract
Despite the increasing use of non-hydrostatic models in the study of wave processes in coastal regions, there is still limited understanding of the non-linear properties of the governing equations and how they improve with increased vertical resolution. In this study, the governing equations of the non-hydrostatic wave model SWASH are analysed and the linear and non-linear solutions up to third-order of all dependent variables are derived, considering one to four vertical layers. The analysis concludes that the model can achieve excellent non-linear properties with respect to the Stokes theory over a large range of water depths using only a few vertical layers. Furthermore, deriving solutions for all variables enables the formulation of improved wave generation and absorption boundary conditions for non-hydrostatic models. A well-known issue of non-linear wave models is related to the generation and propagation of spurious free waves, resulting to non-homogeneous wave fields. In this study, it is proven that by imposing the derived exact mathematical solutions of the governing equations at the model's boundaries, the target first- and second-order wave profiles can be generated with high accuracy, while the spurious waves can be entirely eliminated.
Subject
Improved wave generation
Linear and non-linear properties
Non-hydrostatic model
Sub- and super-harmonics
SWASH
To reference this document use:
http://resolver.tudelft.nl/uuid:cb898485-62a3-4c2c-8660-71cdff21542b
DOI
https://doi.org/10.1016/j.oceaneng.2024.117633
Embargo date
2024-09-27
ISSN
0029-8018
Source
Ocean Engineering, 302
Bibliographical note
Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
Part of collection
Institutional Repository
Document type
journal article
Rights
© 2024 Panagiotis Vasarmidis, Georgios Klonaris, Marcel Zijlema, Vasiliki Stratigaki, Peter Troch