University of Twente Student Theses
Evaluation of Shoreline Changes with Improved One-line Numerical Shoreline Modelling
Sonnemans, R.C. (2023) Evaluation of Shoreline Changes with Improved One-line Numerical Shoreline Modelling.
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| Abstract: | ShorelineS I is a newly developed model that aims at becoming a verified engineering tool that is easy to use and widely applicable for coastal engineers in the near future. By the adaptation of a vector-based grid, and recent improvements that include wave diffraction, ShorelineS has become more accurate in most cases. However, emerged detached breakwaters have remained notoriously difficult for N-line models to simulate properly especially after the case of beaches that connect with the structure. The objective of this research was to “assess different input parameters impacts on shoreline sensitivity in a detached breakwater case study and suggest improvements for one-line numerical shoreline change models”. Therefore, in this thesis, the one-line numerical shoreline change model ShorelineS was first subjected to a sensitivity analysis in for 5 different cases with a detached breakwater where the wave angle and breakwater characteristics were varied. Here, it was found that the use of the Kamphuis longshore transport formulas greatly increased the simulation time. Additionally, the wave height is the most sensitive parameter for the evolution speed of the shoreline. An increase in mean bed slope shifted the shoreline evolution more sideways towards the updrift side. The median grain size showed large differences in sensitivity between the erosion and accretion side of the shoreline. Second, validation tests were performed and the model equilibrium state was compared with the shoreline equilibrium suggested by a spiral bay solution. The validation tests showed the model to predict the salient parameters accurately while tombolos are generally too wide. Especially, near the breakwater dimensionless length boundary condition between a salient or a tombolo, the model was not able to accurately predict the shoreline shape suggested by analytical solutions. The spiral bay solution also showed that the model severely overestimated the static equilibrium shape while subjected to a wave angle. Finally, a first effort was made to implement material exchange between the beach berm and the foreshore bars. This implementation has not been finalized and calibrated due to research constraints. However, the initial test results show a little difference with the original model that suggest that it could have some influence in the final result. It is envisioned that this difference may be greater once the model would also be subjected to seasonally changing wave heights and a dynamic boundary for the bar volumes. |
| Item Type: | Essay (Bachelor) |
| Faculty: | ET: Engineering Technology |
| Programme: | Civil Engineering BSc (56952) |
| Link to this item: | https://purl.utwente.nl/essays/95830 |
| Export this item as: | BibTeX EndNote HTML Citation Reference Manager |
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