Browsing by Author "Wang, Junxian"

Now showing 1 - 6 of 6
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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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    Experimental study of dynamic response of passive flapping hydrofoil in regular wave
    (American Institute of Physics (AIP), 2023-07-26) Wang, Junxian; Santhosh, Sabin; Colomés, Oriol; Capaldo, Matteo; Yang, Liang
    The hydrofoil harnesses wave energy and converts it into thrust. In this paper, we present the results of the first experimental study investigating the dynamic behavior of a fully passive foil with spring-loaded pitch and heave in regular waves. Our study shows that the real-time load signal is multi-harmonic with strong superposition, directly proving the robust energy harvesting performance due to the restoring springs. By interpreting the hydrofoil's pose and path from an image sequence captured underwater, we conclude the dynamic evolution of the fully passive hydrofoil interacting with regular waves. The hydrofoil's dynamics exhibit asymmetric surge, pitch, and heave in a motion cycle. Furthermore, we employ a pixel capturing algorithm with self-correction utility to quantify the hydrofoil's forward displacement from the image sequence of the moving carriage. These findings provide valuable insight into the performance and potential of hydrofoils for marine propulsion.
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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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    Simulation of a floating solar farm in waves with a novel sun-tracking system
    (IOP Publishing, 2023-08-09) Wei, Yujia; Ou, Binjian; Wang, Junxian; Yang, Liang; Luo, Zhenhua; Jain, Sagar; Hetharia, Wolter; Riyadi, Soegeng; Utama, IKAP; Huang, Luofeng
    The awareness of the energy and climate crisis has accelerated the development of renewable energy sources. Photovoltaic (PV) solar power plants harvest clean solar energy and convert it to electricity, which will be one of the most promising alternatives to the power industry in the context of a low-carbon society. Due to its low power density, the traditional deployment of PV systems on land or inland rivers requires much space. Therefore, industries are increasingly interested in expanding offshore Floating PhotoVoltaics (FPV) to oceans, where FPV has less influence on the marine environment and does not occupy precious space for land resources and human activities. This study performs a hydrodynamics-based structural response analysis for a novel FPV system in OpenFOAM. The wave-proof FPV platform is newly designed for this work, which integrated breakwater technologies to sustain the system's survivability in harsh ocean-wave environments. Firstly, the rational mooring types for FPVs installed close to the island are studied considering seabed effects. Subsequently, extensive parametric studies have been conducted to determine a rational design strategy for the mitigation of wave impact. Several potential effects of the proposed platforms on the hydrodynamics in a coastal sea are evaluated for the first time.
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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-assisted propulsion: an experimental study on traveling ships
    (American Institute of Physics (AIP), 2024-02-23) Chan, ChunYin; Wang, Junxian; Yang, Liang; Zang, Jun
    A submerged hydrofoil interacting with incoming waves produces combined heaving and pitching motion, facilitating the conversion of wave energy into thrust. When the foil is attached to the ship hull, the generated “green” power from wave energy could assist the ship's propulsion system and significantly reduce fuel costs. This study experimentally assesses thrust generation from a fixed mid-hull foil by comparing towing force at different wave and traveling speeds. The optimal mid-hull foil demonstrates a fuel cost reduction ranging from 10.3% to 20.4% at diverse traveling speeds and wave parameters. Thrust generation increases at higher traveling speeds. Additionally, this study mathematically describes the hydrofoil motion with an outer pivot, which better suits the ship–foil model. This study then introduces a Strouhal number (⁠StA,S) specifically for the ship–foil model, considering ship travel, ship response, and the hydrofoil's rotation around its outer pivot.