检索结果-南通市图书馆

Numerical and experimental study of internal solitary wave loads on tension leg platforms

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2021年第1期33卷 93-103页

作者： Xu Wang Ji-fu Zhou Key Laboratory for Mechanics in Fluid Solid Coupling System Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Sciences University of Chinese Academy of SciencesBeijing 100049China

With the large-scale density stratified tank and the numerical flume proposed,series of numerical cases in line with the experiments are carried out to investigate the interaction between the tension leg platforms(TLPs)and the internal solitary waves(ISWs).The waveforms,and the loads and the torques on the TLP obtained by the experiments and the simulations agree well with each other.Experimental results show that the amplitudes of the dimensionless horizontal force and torque linearly increase with the dimensionless amplitude,while that of the vertical force increases in a parabolic curve.Besides,the numerical results indicate that the horizontal and vertical forces on the TLP due to the ISWs can be divided into three components,namely,the wave pressure-difference forces,the viscous pressure-difference forces,and the frictional force that is negligible.The wave pressure-difference forces are always the major constituents.However the viscous pressure-difference component is unimportant,it is negligible as compared with the vertical forces.

关键词： Internal solitary waves(ISWs) tension leg platforms(TLPs) wave loads

Study on Transient Gap Resonance with Consideration of the Motion of Floating Body

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Ocean Engineering 2022年第6期36卷 994-1006页

作者： GAO Jun-liang LYU Jing WANG Jing-hua ZHANG Jian LIU Qian ZANG Jun ZOU Tao School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China Key Laboratory of Port Waterway and Sedimentation Engineering of MOTNanjing Hydraulic Research InstituteNanjing 210029China Department of Civil and Environmental Engineering the Hong Kong Polytechnic UniversityHong KongChina Centre for Infrastructure Geotechnical and Water Engineering(IGWE)Department of Architecture and Civil EngineeringUniversity of BathBA27AYU.K Shandong Provincial Key Laboratory of Ocean Engineering Qingdao 266100China

In this paper, the transient fluid resonance phenomenon inside a narrow gap between two adjacent boxes excited by the incident focused waves with various spectral peak periods and focused wave amplitudes is simulated by utilizing the open-sourced computational fluid dynamics software, Open FOAM. The weather-side box is allowed to heave freely under the action of waves, and the lee-side box keeps fixed. This paper mainly focuses on how both the spectral peak period and the focused wave amplitude affect the free-surface amplification inside the gap, the motion of the weather-side box, and the wave loads(including the vertical and the horizontal wave forces) acting on both boxes.For comparison, another two-box system with both boxes fixed is also considered as a control group. It is found that the motion of the weather-side box significantly changes the characteristics of the transient gap resonance, and it would cause that the fluid resonant period becomes 1.4-1.6 times that of the two-box system with both boxes fixed.All the concerned physical quantities(i.e., the free-surface amplification in the gap, the motion of the weather-side box, the wave loads) are found to closely depend on both the spectral peak period and the focused wave amplitude.

关键词： transient gap resonance focused waves free-surface amplification wave loads heave motion OpenFOAM

Hydrodynamic Performance of A Porous-Type Land-Fixed Oscillating Water Column wave Energy Converter

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2022年第1期36卷 1-14页

作者： Robert MAYON NING De-zhi ZHANG Chong-wei Lars JOHANNING State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China College of Engineering Mathematics and Physical SciencesUniversity of ExeterPenryn CampusPenrynCornwallTR109FEUK

A hybrid, porous breakwater-Oscillating Water Column(OWC) wave Energy Converter(WEC) system is put forward and its hydrodynamic performance is investigated using the fully nonlinear, open-source computational fluid dynamics(CFD) model, OpenFOAM. The permeable structure is positioned at the weather side of the OWC device and adjoined to its front wall. A numerical modelling approach is employed in which the interstices within the porous structure are explicitly defined. This permits the flow field development within the porous structure and at the OWC front wall to be observed. The WEC device is defined as a land-fixed, semi-submerged OWC chamber. A range of regular incident waves are generated at the inlet within the numerical tank. The OWC efficiency and the forces on the structure are examined. Results are compared for the simulation cases in which the porous component is present or absent in front of the OWC chamber. It is found that the incorporation of the porous component has minimal effect on the hydrodynamic efficiency of the OWC, reducing the efficiency by less than 5%. Nevertheless,the forces on the front wall of the OWC can be reduced by up to 20% at the higher wave steepness investigated,through inclusion of the porous structure at the OWC front wall. These findings have considerable implications for the design of hybrid OWC-breakwater systems, most importantly in terms of enhancing the durability and survivability of OWC WECs without significant loss of operational efficiency.

关键词： OWC porous breakwater hydrodynamic performance wave loads CFD

Harmonic Analyses of Hydrodynamic Characteristics for Gap Resonance Between Fixed Box and Vertical Wall

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2021年第5期35卷 712-723页

作者： HE Zhi-wei GAO Jun-liang CHEN Hong-zhou ZANG Jun LIU Qian WANG Gang School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China School of Civil Engineering and Architecture Northeast Electric Power UniversityJilin 132012China Centre for Infrastructure Geotechnical and Water Engineering(IGWE)Department of Architecture and Civil EngineeringUniversity of BathBA27AYUK College of Harbour Coastal and Offshore EngineeringHohai UniversityNanjing 210098China

Two marine structures arranged side by side with a narrow gap may suffer from violent free-surface resonance,which would cause green water on deck,dramatically raise hydrodynamic loads on structures and seriously threaten the operation safety.The CFD-based open-sourced software,OpenFOAM?,is employed to simulate the twodimensional fluid resonance inside a narrow gap between a fixed box and a vertical wall induced by regular waves with different wave heights.The topographies with various plane slopes are placed in front of the wall.The focus of this article is on the influences of the incident wave height and the topographic slope on the nonlinear characteristics of various hydrodynamic parameters(including the wave height in the gap,the vertical wave force,and the horizontal wave force on the box)during gap resonance.The ratios of their high-order to the corresponding 1 st-order components under different sets of the incident wave height and the topographic slope are analyzed.It is found that the relative importance of all the high-order components increases gradually with the incident wave height for all the three parameters.The topographic influence on them closely depends on the type of the parameters and the incident wave height.In addition,the occurrence of the 2 nd-order gap resonance phenomenon can cause the 2 nd-order wave height and horizontal force to be significantly larger than the corresponding 1 st-order components.

关键词： gap resonance harmonic analyses resonant wave height wave loads OpenFOAM

A NUMERICAL STUDY ON SIDE HULL OPTIMIZATION FOR TRIMARAN

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2011年第2期23卷 265-272页

作者： XU Min ZHANG Shi-lian State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai 200240 China

Due to the interaction between the main hull and side hulls, different layouts and lengths of side hulls affect the wave loads significantly. Based on three-dimensional potential theory and Green＇s function, this article gives the significant values for wave loads, including vertical shear forces and vertical bending moments at different locations on the main hull, and transverse bending moments at the junction of the cross structure and main hull. In addition, a parametric optimization of wave loads for different layouts and lengths of side hulls were perfomed. Several speeds and wave headings were also considered. Finally, spectral analysis was conducted to attain load distribution. The conclusions of this study are conducive to the design and optimization of this new type of ship

关键词： trimaran three-dimensional potential theory wave loads optimization

An application of network modeling method to scientific research and demonstration platform-Connector load analysis

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2021年第1期33卷 33-42页

作者： Rui Ding Du-lei Yan Hai-cheng Zhang Ye Lu Qi-jia Shi Chao Tian Jia-le Zhang Xin-yun Ni Dao-lin Xu You-sheng Wu College of Mechanical and Vehicle Engineering Hunan UniversityChangsha 410082China China Ship Scientific Research Center Wuxi 214082China

A new approach referred as“the network modeling method”was developed by the authors to analyze the behaviors of marine structures.In this paper the method is briefly described and applied to predict the loads acting on the connectors between the two modules of the Scientific Research and Demonstration Platform(SRDP),which was deployed in a complicated wave environment near islands and reefs in South China Sea.Based on this method,the response amplitude operators(RAOs)of the connector loads of the SRDP in regular waves,and the time variations of the connector loads of the SRDP in an on-site measured random sea state are predicted and presented.The significant stresses at 20 spots of the local connection structure induced by the connector loads in the sea state are further calculated.The comparisons between the predicted and the on-site measured stresses confirm that the network modeling method is feasible to some extent and especially useful for design of the connectors’arrangement,estimation of the connector loads and the related structural safety of a multi-module floating structure in early design stage.

关键词： Network modeling method wave loads hinge type connector on-site measurements Scientific Research and Demonstration Platform(SRDP)

Model Testing for Ship Hydroelasticity: A Review and Future Trends

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2017年第6期22卷 641-650页

作者：焦甲龙任慧龙陈超核 School of Civil Engineering and Transportation South China University of Technology College of Shipbuilding Engineering Harbin Engineering University

Conducting model experiments is an effective and reliable way in the investigation of ship hydrodynamic and hydroelastic behaviors. A survey of model testing techniques for ship hydroelasticity and its prospect are presented in this paper. The research highlights with respect to ship hydroelasticity and key points in model testing are summarized at first. Then testing techniques including laboratory tank test and full-scale sea trial are reviewed, and both their advantages and disadvantages are analyzed comprehensively. Based on the conventional testing approaches, a state-of-the-art testing approach which includes performing tests using large-scale model at sea is proposed. Furthermore, recommendations towards the further development of ship hydroelasticity tests are forecasted and discussed.

关键词： ship hydroelasticity wave loads model testing sea trial large-scale model

在线全文

学校读者我要写书评

暂无评论

水下波能装置的波致弹性变形研究

Journal of Marine Science and Application 2020年第3期19卷 317-338页

作者： Shuijin Li Masoud Hayatdavoodi R.Cengiz Ertekin Civil Engineering Department School of Science and EngineeringUniversity of DundeeDundee DD14HNUK College of Shipbuilding Engineering Harbin Engineering UniversityHarbin 150001China

Structural integrity has remained a challenge for design and analysis of wave energy devices.A difficulty in assessment of the structural integrity is often laid in the accurate determination of the wave-induced loads on the wave energy devices and the repones of the structure.Decoupled hydroelastic response of a submerged,oscillating wave energy device to extreme nonlinear wave loads is studied here.The submerged wave energy device consists of an oscillating horizontal disc attached to a direct-drive power take-off system.The structural frame of the wave energy device is fixed on the seafloor in shallow water.Several extreme wave conditions are considered in this study.The nonlinear wave loads on members of the submerged structure are obtained by use of the level I Green-Naghdi equations and Morison’s equation for cylindrical members.Distribution of Von Mises stresses and the elastic response of the structure to the extreme wave loads are determined by use of a finite element method.The decoupled hydroelastic analysis of the structure is carried out for devices built by four different materials,namely stainless steel,concrete,aluminium alloy,and titanium alloy.The elastic response of these devices is studied and results are compared with each other.Points of maximum stress and deformations are determined and the structural integrity under the extreme conditions is assessed.It is shown that the proposed approaches provide invaluable information about the structural integrity of wave energy devices.

关键词： Renewable energy wave energy converter wave loads Hydroelasticity Green-Naghdi equations

Hydrodynamic Performance of A New Concept of Spar

在线全文

学校读者我要写书评

暂无评论

Hydrodynamic Performance of A New Concept of Spar