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Wave Protection Effect of Periodic Row of Bottom-Hinged Flap-Type Wave Energy Converters

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Transactions of Tianjin University 2016年第6期22卷 563-571页

作者：王冬姣邱守强叶家玮梁富琳 School of Civil engineering and Transportation South China University of Technology Guangzhou 510640 China

A flap-type wave energy converter(WEC) is combined with a nearshore breakwater to expand the application of WECs both economically and environmentally. Based on the linear potential theory, an eigenfunction expansion solution is developed for a periodic row of bottom-hinged flap-type WECs exposed to normal waves. Additionally, the viscous effect is considered using the ship rolling solution method with a viscous damping term included in the equation of motion, and the viscous damping expression is also described. The proposed solution is verified by comparison with published literatures. The results including the wave energy conversion efficiency, the reflected and transmitted proportion of the incident wave energy are presented for a range of wave periods and geometric ratios. It is demonstrated that better wave protection effects can be attained with smaller gaps between the WECs, where the transmitted proportion of the incident wave energy is lower. An optimal geometric ratio thus exists for a given wave power absorption and a specific wave period.

关键词： wave energy converter bottom-hinged flap eigenfunction expansion wave protection

Hydrodynamics of a dual-module pontoon-net floating breakwater system:Numerical simulations and prototype tests

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Journal of Hydrodynamics 2021年第5期33卷 915-927页

作者： Yong Cheng Chun-yan Ji Xue-kang Gu Fa-liHuo Jie Cui Zhi-Ming Yuan School of Naval Architecture and ocean engineering Jiangsu University of Science and TechnologyZhenjiang 212003China China ship Scientific Research Center Wuxi 214082China Department of Naval Architecture Ocean and Marine EngineeringUniversity of StrathclydeGlasgowUK

Floating breakwaters with a mooring system have been widely applied to protect marine infrastructures(e.g.,artificial beach or island,aquaculture farm or marine vessels in harbors)from being destroyed by severe *** this paper,an innovative cylindrical dual pontoon-net floating breakwater was developed to enhance the wave attenuation *** dual-module floating breakwater system was constructed as the prototype for on-site testing.A fully nonlinear time-domain model based on the coupled iterative solutions of the fluid integral equation and the pontoon-net dynamic equations was proposed to simulate the interactions between waves and the floating breakwater *** flow field around the nets was simulated by introducing a porous-media model with Darcy’s law,while the deformation of the flexible nets was solved by using the lumped mass *** instantaneous free surface was captured using the mixed Eulerian-Lagrangian(MEL)approach which employs an improved moving-grid technique based on the spring analysis to re-mesh the instantaneous water surface and the body wetted ***-site tests were also conducted to evaluate wave transmission performance of the floating breakwater system and to validate the numerical *** comparisons show that the numerical solutions are in good agreement with the measured *** effects of incident wave direction,wave period,wave height,net height,net number and net porosity on the hydrodynamic performance of the floating breakwater system were emphatically examined.

关键词： Floating breakwater fully nonlinear simulations on-site tests flexible net wave attenuation moving-grid technique

Wave Slamming on An OWSC Wave Energy Converter in Coupled Wave-Current Conditions with Variable-Depth Seabed

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China ocean engineering 2021年第5期35卷 646-661页

作者： CHENG Yong JI Chun-yan YUAN Zhi-ming Atilla INCECIK School of naval architecture and ocean engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Naval Architecture Ocean and Marine Engineering DepartmentUniversity of StrathclydeGlasgowUnited Kingdom

Coastal wave energy resources have enormous exploitation potential due to shorter weather window,closer installation distance and lower maintenance ***,impact loads generated by depth variation from offshore to nearshore and wave-current interaction,may lead to a catastrophic damage or complete destruction to wave energy converters(WECs).This objective of this paper is to investigate slamming response of a coastal oscillating wave surge converter(OWSC)entering or leaving water *** on fully nonlinear potential flow theory,a time-domain wave-current-structure interaction model combined with higher-order boundary element method(HOBEM),is developed to analyze the coupled hydrodynamic *** variable-depth seabed is considered in the model to illustrate the shallow water effect on impact loads and free surface profiles in coastal zone.A domain decomposition approach is utilized to simulate the overlapping phenomenon generated by a jet falling into water under gravity *** a series of Lagrangian interpolation methods,the meshes on boundaries are rearranged to avoid the mismatch between element size on free surface and body *** present model is validated against the existing experimental and numerical *** are also provided for the effects of wave-current interaction and uneven local seabed on the slamming *** is found that the length of the splash jet increases for a following current and decreases for an opposing current,and that the slamming response of the OWSC device is sensitive to the geometric features of the uneven seabed.

关键词： wave-current interaction oscillating wave surge converter fully nonlinear potential flow theory slamming response higher-order boundary element method

On the mathematically reliable long-term simulation of chaotic solutions of Lorenz equation in the interval [0,10000]

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Science China(Physics,Mechanics & Astronomy) 2014年第2期57卷 330-335页

作者： LIAO ShiJun WANG PengFei state key laboratory of ocean engineering School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong University Nonlinear Analysis and Applied Mathematics Research Group (NAAM) King Abdulaziz University (KAU) state key laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences

Using 1200 CPUs of the National Supercomputer TH-A1 and a parallel integral algorithm based on the 3500th-order Taylor expansion and the 4180-digit multiple precision data,we have done a reliable simulation of chaotic solution of Lorenz equation in a rather long interval 0 t 10000 LTU(Lorenz time unit).Such a kind of mathematically reliable chaotic simulation has never been *** provides us a numerical benchmark for mathematically reliable long-term prediction of ***,it also proposes a safe method for mathematically reliable simulations of chaos in a finite but long enough *** addition,our very fine simulations suggest that such a kind of mathematically reliable long-term prediction of chaotic solution might have no physical meanings,because the inherent physical micro-level uncertainty due to thermal fluctuation might quickly transfer into macroscopic uncertainty so that trajectories for a long enough time would be essentially uncertain in physics.

关键词： chaos reliable simulation uncertainty propagation

Research of Underwater Self-Reconfigurable System

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Journal of Shanghai Jiaotong university(Science) 2014年第1期19卷 35-40页

作者：吴超葛彤庄广胶刘建民 state key laboratory of ocean engineering Shanghai Jiaotong University

This article describes a novel underwater robot, which is called underwater self-reconfigurable system(USS). USS is studied and developed by Shanghai Jiao Tong University. It is formed by a quantity of the same modules and works in group. Based on that, USS can change its form while working in the complicated underwater structures according to diffierent tasks. New multi-jaw underwater docking system, piston style regulator and clamshell-like sampling module are designed for USS, these developments address the problems of underwater docking, floating condition adjusting and sampling. Besides, the gaits like wriggle, creeping, swimming and fourlegged moving have been successfully implemented in tank and lake test, which verifies the validity of the concept.

关键词： self-reconfigurable robot underwater docking static stability module gait

Risk-Identification-Based Hybrid Method for Estimating the System Reliability of Existing Jacket Platforms Under Fire

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Journal of Shanghai Jiaotong university(Science) 2013年第1期18卷 70-75页

作者：许继祥赵金城段海娟 Department of Civil engineering Shanghai Jiaotong University

This paper proposes a risk-identification-based hybrid method for estimating the system reliability of steel jacket structures under *** proposed method starts with risk identification;according to the results of hazard identification and Dow’s fire and explosion index(F&EI) methodology,the most dangerous hazard sources are *** term of each equipment layout in steel jacket structures,fire load is imposed and elasto-plastic analysis is *** to the deformed state of steel jacket structures,the weakest failure mode of steel jacket structures is *** order to know the effect on ultimate bearing capacity of the offshore structural system,a series of elasto-plastic analyses are performed in which single failure element contained in the weakest failure mode is removed from the whole offshore platform structural ***,the failure function of the steel jacket structure is generated and the failure probability of the steel jacket structure system is estimated under fire by genetic algorithm via MATLAB program.

关键词： hazard identification (HAZID) steel jacket structure relative importance factor failure probability genetic algorithm (GA)

Prediction of Streamwise Flow-Induced Vibration of A Circular Cylinder in the First Instability Range

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China ocean engineering 2012年第4期26卷 555-564页

作者：徐万海余建星杜杰成安康康昊 state key laboratory of Hydraulic engineering Simulation and Safety School of Civil EngineeringTianjin University

The streamwise flow-induced vibration of a circular cylinder with symmetric vortex shedding in the first instability range is investigated, and a wake oscillator model for the dynamic response prediction is proposed. An approach is applied to calibrate the empirical parameters in the present model; the numerical and experimental results are compared to validate the proposed model. It can be found that the present prediction model is accurate and sufficiently simple to be easily applied in practice.

关键词： streamwise flow-induced vibrations circular cylinder wake oscillator model first instability range

An anthropomorphic controlled hand prosthesis system

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第10期13卷 769-780页

作者： Hai HUANG Hong LIU Nan LI Li JIANG Da-peng YANG Lei WAN Yong-jie PANG Gerd HIRZINGER National key laboratory of Science and Technology on Autonomous Underwater Vehicle Harbin Engineering University Harbin 150001 China state key laboratory of Robot and Systems Harbin Institute of Technology Harbin 150001 Chin Institute of Robotics and Mechatronics German Aerospace Center DLR Wessling 82230 Germany

Based on HIT/DLR(Harbin Institute of Technology/Deutsches Zentrum für Luft-und Raumfahrt) Prosthetic Hand II,an anthropomorphic controller is developed to help the amputees use and perceive the prosthetic hands more like people with normal physiological *** core of the anthropomorphic controller is a hierarchical control *** is composed of a top controller and a low level *** top controller has been designed both to interpret the amputee's intensions through electromyography(EMG) signals recognition and to provide the subject-prosthesis interface control with electro-cutaneous sensory feedback(ESF),while the low level controller is responsible for grasp *** control strategies include the EMG control strategy,EMG and ESF closed loop control strategy,and voice control *** EMG signal recognition,10 types of hand postures are recognized based on support vector machine(SVM).An anthropomorphic closed loop system is constructed to include the customer,sensory feedback system,EMG control system,and the prosthetic hand,so as to help the amputee perform a more successful EMG *** results suggest that the anthropomorphic controller can be used for multi-posture recognition,and that grasp with ESF is a cognitive dual process with visual and sensory *** process while outperforming the visual feedback process provides the concept of grasp force magnitude during manipulation of objects.

关键词： Anthropomorphic controller Prosthetic hand EMG recognition Electro-cutaneous sensory feedback

Null subcarriers based Doppler scale estimation with polynomial interpolation for multicarrier communication over ultrawideband underwater acoustic channels

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Journal of Systems engineering and Electronics 2015年第6期26卷 1177-1183页

作者： Yang Chen Jingwei Yin Ling Zou Dan Yang Yuan Cao School of Information Science and engineering Changzhou University College of Underwater Acoustic engineering Harbin Engineering University School of Textile and Material engineering Wuhan Textile University School of Electrical and Electronic engineering Nanyang Technological University

This paper addresses the extremal problem of the null subcarriers based Doppler scale estimation in underwater acoustic （UWA） orthogonal frequency division multiplexing （OFDM） communication. The cost function constructed of the total energy of null subcarriers through discrete Fourier transform （DFT） is proposed. The frequencies of null subcarriers are identified from non-uniform Doppler shift at each tentative scaling factor. Then it is proved that the cost function can be fitted as a quadratic polynomial near the global minimum. An accurate Doppler scale estimation is achieved by the location of the global scarifying precision and increasing the computation minimum through polynomial interpolation, without complexity. A shallow water experiment is conducted to demonstrate the performance of the proposed method. Excellent performance results are obtained in ultrawideband UWA channels with a relative bandwidth of 67%, when the transmitter and the receiver are moving at a relative speed of 5 kn, which validates the proposed method.

关键词： underwater acoustic (UWA) communication orthogo-nal frequency division multiplexing (OFDM) Doppler scale estimation polynomial interpolation.