Browsing by Author "Xing, Jingru"

Now showing 1 - 7 of 7
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    Experimental investigation of wave induced flapping foil for marine propulsion: heave and pitch stiffness effect
    (AIP, 2024-04-15) Wang, Junxian; Xing, Jingru; Siddiqui, M. Salman; Stawiarska, Adriana; Yang, Liang
    The submerged hydrofoil has the capability to harness wave energy and convert it into thrust to work with the ship's power system. The current series of experiments investigated the interaction of a passive submerged hydrofoil with regular waves through a comparison of the generated horizontal forces. Springs provide the restoring force for the hydrofoil's heave/pitch motion, corresponding to heave spring and pitch spring. Maintaining a constant heave spring stiffness (490 N/m), subsequent statistical analysis summarized the force trends at different pitch stiffnesses (16–300 N/m) and suggested an optimal pitch spring stiffness in regular waves. A pulse-shaped force signal was observed and explained as a result of low pitch stiffness. Experiments with different spring setups revealed that the heave spring contributes to the harmonic force generated by the fully passive foil. Additionally, by varying wave conditions with limited wave amplitudes and frequencies, tests reproduced the variation of force signals over time and assessed their dependence on wave parameters.
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    Numerical investigation of wave induced thrust on a submerged hydrofoil
    (AIP Publishing, 2024-09-01) Xing, Jingru; Stagonas, Dimitris; Hart, Phil; Zhang, Chengchun; Yang, Jianhui; Yang, Liang
    Submerged flapping hydrofoils have the capability to directly convert wave energy into thrust, offering a sustainable approach to marine propulsion. This research employs computational fluid dynamics (CFD) to analyze the propulsion mechanism of wave-induced flapping hydrofoils. Initially validated through established benchmarks and experimental results with foil in uniform flow, the CFD model was then applied to examine the generation of thrust by flapping hydrofoils in heading regular wave. The study reveals a distinct transition from drag to thrust, characterized by the patterns of vortex flow. For the first time, the influence of pitch stiffness on this propulsion process is extensively explored, identifying optimal wave conditions and pitch stiffness for the application of future eco-friendly marine systems.
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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.
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    Numerical simulation of stabilisation of floating wind with submerged hydrofoil
    (IOP Publishing, 2024-06-10) Wang, Junxian; Yang, Liang; Xing, Jingru; Yang, Jianhui
    This research focuses on the optimal design and method of attaching a submerged hydrofoil to an offshore platform to enhance stabilisation. The flapping hydrofoil, exhibiting a hybrid motion combining heave and pitch, is engineered to convert incoming wave energy. It generates a distinctive wake that effectively counteracts incoming waves, thereby reducing wave impact. In this study, a NACA0030-type hydrofoil was strategically positioned between two columns of the platform model. Comprehensive analyses were conducted to evaluate the free-floating platform's response to regular waves, with a focus on the attached hydrofoil. The results indicate that the hydrofoil significantly reduces the surge motion and drifting speed of the platform, affirming its effectiveness in enhancing stabilisation.
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    Wave devouring propulsion for stabilizing floating wind turbine platform: experimental study
    (Elsevier, 2025-01-01) Xing, Jingru; Wang, Junxian; Matin, Ashkan; Vaidya, Ninad Prashant; Yang, Liang; Townsend, Nicholas; Zuo, Lei
    Wave Devouring Propulsion (WDP) is a green propulsion method that uses submerged foils to convert wave energy into thrust, serving both as an auxiliary propulsion system and as a stabilizer for maritime structures. This study highlights WDP's effectiveness in improving stability for semi-submersible offshore wind turbine platforms. Experiments on a 1:100 scaled model in regular and irregular head wave conditions were conducted in both free-floating conditions, and with a mooring system to validate WDP's effectiveness. Results show that the integrated foil design reduced mooring line tension by 41.07% compared to the design without foils in specific scenarios, suggesting a promising avenue for future research and application.
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    Wave devouring propulsion: an overview of flapping foil propulsion technology
    (Elsevier, 2023-07-29) Xing, Jingru; Yang, Liang
    A comprehensive review of flapping foils for Wave Devouring Propulsion (WDP) is presented. The flapping foil can effectively utilize wave energy and generate thrust. The development of WDP is discussed, followed by an introduction to the geometry, modes of motion, and operating principles. These research studies are classified as theoretical, experimental, and numerical and are provided in detail. They demonstrate that marine equipment with a flapping foil system can achieve high energy conversion efficiency and low resistance. Several prototypes of the combination of WDP with human-crewed and uncrewed vessels have been shown, including the latest initial concept models and company products. There is a huge prospect for self-driven, pollution-free propulsion of marine devices, and this paper suggests several future studies.