Coupling of NAMI DANCE and XBeach numerical models to simulate tsunami induced morphological changes: Case study in Sığacık bay


Thesis Type: Postgraduate

Institution Of The Thesis: Middle East Technical University, Faculty of Engineering, Department of Civil Engineering, Turkey

Approval Date: 2022

Thesis Language: English

Student: YAĞIZ ARDA ÇİÇEK

Principal Supervisor (For Co-Supervisor Theses): Ahmet Cevdet Yalçıner

Co-Supervisor: Cüneyt Baykal

Abstract:

In this study, NAMI DANCE and XBeach Non-hydrostatic numerical models are coupled to assess the tsunami-induced morphological changes. The former is faster than most tsunami numerical models due to its graphics processing unit support, and the latter solves flow-induced morphological changes and dispersive flow equations. Four simulation studies, including the individual model comparison of hydrodynamics, one- and two-dimensional coupled model validation, and a case study assessing morphological changes inside Teos Marina, Izmir, due to the 30 October 2020 Samos Earthquake Tsunami, are conducted. The hydrodynamic model performance of NAMI DANCE and XBeach Non-hydrostatic is found comparable. Additionally, one- and two-dimensional coupled models are validated against the modeling of solitary wave-induced cross-shore profile changes and hypothetical long wave propagation on a complex bathymetry study, respectively. Case study model results show that the material eroded from the marina entrance is deposited at the marina center due to decelerating flow. Additionally, a poor morphologic model performance at the marina entrance is obtained, whereas the coupled model performed better in the regions inside the marina. However, it is unclear to the author whether the low performance is obtained due to the coupling method followed or the low-quality and old pre-event bathymetry data used in both quantitative and qualitative comparisons. During the simulation studies, the effects of several XBeach Non-hydrostatic input parameters on the morphologic performance are evaluated, and it is concluded that the morphologic accuracy is significantly affected by sediment transport formulation.