Browsing by Author "Chen, Songgui"

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    Numerical modelling of new flap-gate type breakwater in regular and solitary waves using one-fluid formulation
    (Elsevier, 2021-10-20) Chen, Songgui; Xing, Jingru; Yang, Liang; Zhang, Huaqing; Luan, Yingni; Chen, Hanbao; Liu, Haiyuan
    Breakwater is commonly used infrastructure for protecting coastal zones from waves and tsunamis. Computational modelling is frequently employed for prediction and validation of the breakwater design. Potential flow based models may not be ideal for such applications due to large energy dissipation. We apply the Computational Fluid Dynamics (CFD) to study the waves and breakwater interaction problem. In this work, we benchmark the performance of a new type of flap-gate breakwater in regular waves (airy wave theory and second order Stokes wave theory), where the multiphase Navier–Stokes equations are solved and the structure of breakwater is considered as one phase of fluid within the ‘one-fluid’ framework. In this way, the computational costs will be reduced to the same level as the numerical wave tank alone. We conduct a grid refinement study and compare results to experiments to investigate accuracy. The result shows a good agreement with the experimental data. Further, we use the validated model for sensitivity studies for different settings of flap-gate, and the solitary waves paradigm for tsunamis. The proposed novel numerical tool allows us to study large parametric spaces, impact of breaking waves, load and pressure producing process and interaction time.
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    Numerical modelling of oil containment process under current and waves
    (Elsevier, 2023-04-11) Xing, Jingru; Chen, Songgui; Stagonas, Dimitris; Yang, Liang
    This study presents a novel three-phase Fluid–Structure Interaction (FSI) model for simulating the containment of oil spills. The model uses Level Sets to capture the evolution of multiple interfaces and incorporates spring forces on the structure under hybrid wave–current boundary conditions. The implementation of spring forces has been validated through simple harmonic motion models and a wedge falling simulation demonstrates the model’s ability to handle multi-phase deformation. The study compares numerical results with experimental data to study the response of oil spills to wave–current hybrid conditions. Our simulations reveal that when the current exceeds 0.2 m/s, the movement of the boom is dominated by the current and not by the waves or their inertia, providing important information for the design of effective oil spill containment systems.