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Investigation of infragravity waves in a two-dimensional domain using non-hydrostatic numerical model, SWASH

Alavantas, N. (2015) Investigation of infragravity waves in a two-dimensional domain using non-hydrostatic numerical model, SWASH.

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Abstract:Infragravity waves (IG) are generated due to the non-linear interactions between the short (in terms of length) waves. IG waves propagate bounded to the short wave groups and they are released when fluctuations to the short wave energy occur. Aim of this research is to determine the behavior of IG waves around and inside the two-dimensional domain of Barbers Point Harbour on the island of Oahu, Hawaii, USA. In order to achieve simulation of IG waves, an extensive investigation is taking place, aiming to propose the most accurate numerical wave model for the particular case. The conclusion is that an efficient simulation of the harbour domain needs the usage of a phase-resolving and nonlinear wave model, SWASH. SWASH showed consistency for the IG wave calculation(inside the basin of Barbers Point harbour) and its predictive skill measured approximately 0:84. Finally a further analysis is taking place, in order to decompose the IG signal. Aim is to separate the IG waves to free and bounded by using bispectral analysis and the separation method proposed by Sheremet et al. [2002]. The results are presented for the area outside the harbour. IG waves seem to be generated 500m seawards of the inlet. Additionally, the shore is identified as partially re ective boundary, even for the IG waves (R2 IG = 0:6). Finally, the behavior of the IG waves are affected by the entrance channel. IG waves (as long waves) are strongly refracted by the channel and continue to propagate inside the basin, when the short waves follow another path, leading to the adjacent shores.
Item Type:Essay (Master)
Faculty:ET: Engineering Technology
Subject:56 civil engineering
Programme:Civil Engineering and Management MSc (60026)
Link to this item:https://purl.utwente.nl/essays/67538
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