Numerical modelling of wave-structure interaction problems through CFD methods

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Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Bilimleri Enstitüsü, Türkiye

Tezin Onay Tarihi: 2020

Tezin Dili: İngilizce

Öğrenci: HASAN GÖKHAN GÜLER

Asıl Danışman (Eş Danışmanlı Tezler İçin): Ahmet Cevdet Yalçıner

Eş Danışman: Cüneyt Baykal

Özet:

The major focus of this study is the computational fluid dynamics (CFD) modelling of wave-structure interaction problems. In the first part of this study, the performance of Haydarpaşa Breakwater under tsunami attack is assessed both experimentally and numerically. It is concluded that the major failure mechanism of this breakwater is the sliding of the crown-wall, and the stability of the stones located at the harbour side is also significant. Design recommendations are given based on the stability of the single stone located at the top layer at the harbour side of the breakwater. Next, the motion and collision of two spherical particles under solitary wave attack are studied both experimentally and numerically. The strengths and weaknesses of the two available CFD solvers used in these studies are discussed. In the second part of this study, two CFD solvers are developed and validated using OpenFOAM CFD Library regarding the discussions in the first part. Both models are capable of solving flow properties inside the porous medium, capturing the free-surface using the Volume of Fluid (VOF) Method, and linked to wave generation and absorption boundary conditions previously established in this library. The first CFD solver is based on the body-force immersed boundary method (IBM) for stationary boundaries. VOF method is applied using both algebraic and geometric algorithms in this solver. It is the first time that the geometric method called isoAdvector is used with IBM and within the porous media. This numerical solver is validated against four experimental datasets in comparison with a CFD solver working on conventional body-fitted grids. The second numerical model is based on the cut-cell IBM for both stationary and moving boundaries. This model is the first example that considers the moving boundaries, free-surface, porous media flow and wave generation/absorption in the same numerical model and validated against data from an analytical study.