Commercial vessels have recently been increasing in size to meet the fast-growing demand for transportation and operations. However, this trend may result in more flexible or "softer" hulls. The flexible hull structure and high operational speed requirements bring the ship's natural frequency closer to the wave encounter frequency, increasing the probability of resonance or high-frequency vibrations. Therefore, hydroelastic effects and relevant loads should be considered when designing wave loads and evaluating the strength of large ships. A robust numerical model is in search of ship designers and regulators, intended to predict the impact of hydroelasticity in the initial stages of design as per the design regulations, where there exists a greater opportunity to make modifications and utilise high-fidelity tools to verify the performance of advanced designs. This study aims to fill this gap by performing robust numerical investigations based on open-source software on the seakeeping and hydroelastic analysis of a monohull under wave excitations. Firstly, a detailed literature review is presented to overview the previous theoretical and numerical methods for ship hydroelasticity. This review also includes a general comparison between these hydroelastic techniques and discusses the differences.Following this, two fully coupled CFD-based unsteady FSI numerical frameworks are established: coupled CFD-FEA and CFD-DMB methods, respectively. The physical principle of these FSI models is to treat a ship’s surface hull as an elastic body and interact with its surrounding flow field to form a fully coupled system. Taking advantage of the present numerical models, the hydroelastic behaviours of a containership, such as its vertical bending displacement and corresponding bending moment, can be quantified, and the “springing” and “whipping” behaviour can be measured. It is believed that the present FSI model will exhibit more advantages over the traditional rigid-body method in the ship seakeeping field.Later, the presented CFD-DMB model is further extended for its application to irregular extreme waves and damaged ship conditions. The results achieved from these studies could also help to assess the structural integrity and longitudinal strength of a ship (intact or damaged), which serves as an improved technique for regulations to evaluate conventional ship designs.Finally, the results drawn from each chapter of this thesis are summarised and discussed, and recommendations are made for future research.
Date of Award | 27 Jul 2023 |
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Original language | English |
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Awarding Institution | - University Of Strathclyde
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Sponsors | University of Strathclyde |
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Supervisor | Atilla Incecik (Supervisor) & Maurizio Collu (Supervisor) |
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