检索结果-南通市图书馆

A framework for efficient irregular wave simulations using Higher Order Spectral method coupled with viscous two phase model

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 Ocean Engineering and Science 2017年第4期2卷 253-267页

作者： Inno Gatin Vuko Vukčević Hrvoje Jasak faculty of Mechanical Engineering and naval architecture University of ZagrebIvana Lučića 5ZagrebCroatia Wikki Ltd. 459 Southbank HouseSE17SJ LondonUnited Kingdom

In this paper a framework for efficient irregular wave simulations using Higher Order Spectral method coupled with fully nonlinear viscous,two-phase Computational Fluid Dynamics(CFD)model is *** model is based on solution decomposition via Spectral Wave Explicit Navier-Stokes Equation method,allowing efficient coupling with arbitrary potential flow *** Order Spectrum is a pseudo-spectral,potential flow method for solving nonlinear free surface boundary conditions up to an arbitrary order of *** is capable of efficient long time nonlinear propagation of arbitrary input wave spectra,which can be used to obtain realistic extreme *** facilitate the coupling strategy,Higher Order Spectrum method is implemented in foam-extend alongside the CFD *** of the Higher Order Spectrum method is performed on three test cases including monochromatic and irregular wave ***,the coupling between Higher Order Spectrum and CFD is validated on three hour irregular wave ***,a simulation of a 3D extreme wave encountering a full scale container ship is shown.

关键词： Higher Order Spectral method Irregular waves Extreme waves CFD Foam-extend

Probabilistic Indicators of Structural Redundancy in Mechanics

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

World Journal of Mechanics 2012年第5期2卷 229-238页

作者： Branko Blagojevic Kalman Ziha Department of Mechanical Engineering and naval architecture Faculty of Electrical EngineeringMechanical Engineering and Naval Architecture(FESB)University of SplitSplitCroatia Department of Ship Structures Faculty of Mechanical Engineering and Naval Architecture(FSB)University of ZagrebZagrebCroatia

The paper in the introductory part reviews various definitions and interpretations of structural redundancy in mechanics. The study focuses on the general structural redundancy of systems after sequences of component failures followed by possible load redistributions. The second section briefly summarizes the Event Oriented System Analysis and structural redundancy in terms of the conditional probabilistic entropy. Mechanical responses to adverse loads in this approach are represented by random operational and failure events in the lifetime. The general redundancy measure in the third section of the paper employs the information entropy and goes beyond existing formulations since it includes all functional modes in service. The paper continues with a summary of traditional redundancy indices. In addition, it proposes an alternative redundancy index that accounts for the transition to secondary functional level in case of failures of primary components. The example of a ship structure illustrates the usage of the conditional entropy of subsystems of operational events and compares it to the traditional and newly proposed redundancy indices. The study at the end investigates how to enhance the safety of structures by using the redundancy based design.

关键词： Reliability Event-Oriented System Analysis Entropy Redundancy Redundancy Index Structures

Numerical Investigation on Drag Reduction Effect by Mass Injection from Porous Boundary Wall

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

Transactions of Nanjing University of Aeronautics and Astronautics 2015年第2期32卷 250-254页

作者：赵勇高云姜宗玉王天霖邹丽 Transportation Equipment and Ocean Engineering College Dalian Maritime University State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University State Key Laboratory of Oil and Gas Reservoir Geology and Exploration Southwest Petroleum University Wood Group Mustang School of naval architecture Dalian University of Technology

Interaction between the injected flow from the porous wall and the main flow can reduce drag *** phenomenon is significant to the flight vehicle *** intensive flux of injection enhances difficulty of numerical simulation and requires higher demands on the turbulence model.A turbulent boundary layer flow with mass injection through a porous wall governed by Reynolds averaged Navier-Stokers(RANS)equations is solved by using the Wilcox′s k-ωturbulence model and the obtained resistance coefficient agrees well with the experimental *** results with and without mass injection are compared with other conditions *** profile,turbulent kinetic energy and turbulent eddy viscosity are studied in these two *** confirm that the boundary layer is blowing up and the turbulence is better developed with the aid of mass injection,which may explain the drag reduction *** numerical simulation may deepen our comprehension on this complex flow.

关键词： mass injection boundary layer blowing up drag reduction turbulence model Reyndds averaged Navier-Stokers(RANS)

Scaling Behavior of Bulk Freight Rate Volatility Before and After Noise Reduction

在线全文

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2016年第6期21卷 655-661页

作者：代思宇陈飞儿曾亚东曾鑫 State Key Laboratory of Ocean Engineering School of Naval Architecture Ocean and Engineering Shanghai Jiaotong University Shanghai 200240 China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration Shanghai 200240 China College of Transport and Communications Shanghai Maritime University Shanghai 201306 China

Analysis of freight rate volatility characteristics is a hot topic after year 2008 due to the effect of financial crisis in marine *** this paper,we analyze the bulk freight rate index by detrended fluctuation analysis(DFA) method and discover the scaling *** points(SPs),as the indicators of scaling behavior,can be eliminated after Vondr′ak noise reduction ***,we conclude that highfrequency noise is the cause of SP.

关键词： bulk freight rate noise reduction detrended fluctuation analysis(DFA) Vondr′ak filtering scaling behavior

Fuel Saving and Emissions Cut Through Shore-Side Power Concept for High-speed Crafts at the Red Sea in Egypt

在线全文

学校读者我要写书评

暂无评论

Journal of Marine Science and Application 2013年第4期12卷 463-472页

作者： Ibrahim S.Seddiek Mosaad A.Mosleh Adel A.Banawan Department of Marine Engineering Technology Arab Academy for Science & Technology and Maritime Transport Department of Marine engineering Faculty of Maritime Studies King Abdul-Aziz University Department of Marine Engineering and naval architecture Faculty of Engineering Alexandria University

The progress of economic globalization,the rapid growth of international trade,and the maritime transportation has played an increasingly significant role in the international supply *** a result,worldwide seaports have suffered from a central problem,which appears in the form of massive amounts of fuel consumed and exhaust gas fumes emitted from the ships while *** ports have taken the necessary precautions to overcome this problem,while others still suffer due to the presence of technical and financial *** this paper,the barriers,interconnection standards,rules,regulations,power sources,and economic and environmental analysis related to ships,shore-side power were studied in efforts to find a solution to overcome his *** a case study,this paper investigates the practicability,costs and benefits of switching from onboard ship auxiliary engines to shore-side power connection for high-speed crafts called Alkahera while berthed at the port of Safaga,*** results provide the national electricity grid concept as the best economical selection with 49.03 percent of annual cost ***,environmentally,it could achieve an annual reduction in exhaust gas emissions of CO2,CO,NOx,P.M,and SO2by 276,2.32,18.87,0.825 and 3.84 tons,respectively.

关键词： exhaust gas Egyptian national electric grid high-speed crafts Safaga port ships’ shore-side power ship emissions ship fuel saving

The use of metal hydrides in fuel cell applications

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2017年第1期27卷 3-20页

作者： Mykhaylo V.Lototskyy Ivan Tolj Lydia Pickering Cordellia Sita Frano Barbir Volodymyr Yartys HySA Systems Competence Centre South African Institute for Advanced Materials Chemistry (SAIAMC) University of the Western Cape University of Split Faculty of Electrical Engineering Mechanical Engineering and Naval Architecture Department of Thermodynamics and Heat Engines Institute for Energy Technology Kjeller

This paper reviews state-of-the-art developments in hydrogen energy systems which integrate fuel cells with metal hydride-based hydrogen storage. The 187 reference papers included in this review provide an overview of all major publications in the field, as well as recent work by several of the authors of the review. The review contains four parts. The first part gives an overview of the existing types of fuel cells and outlines the potential of using metal hydride stores as a source of hydrogen fuel. The second part of the review considers the suitability and optimisation of different metal hydrides based on their energy efficient thermal integration with fuel *** performances of metal hydrides are considered from the viewpoint of the reversible heat driven interaction of the metal hydrides with gaseous H;. Efficiencies of hydrogen and heat exchange in hydrogen stores to control H;charge/discharge flow rates are the focus of the third section of the review and are considered together with metal hydride – fuel cell system integration issues and the corresponding engineering solutions. Finally, the last section of the review describes specific hydrogen-fuelled systems presented in the available reference data.

关键词： Fuel cells Hydrogen storage Metal hydrides Thermal integration System development

ISS-based robust adaptive fuzzy algorithm for maintaining a ship's track

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Marine Science and Application 2007年第4期6卷 1-7页

作者： LI Tie-shan YAN Shu-jia QIAO Wen-ming School of naval architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai 200030 China Navigation College Dalian Maritime University Dalian 116026 China Navigation School Shandong Jiaotong College Weihai 250023 China

This paper focuses on the problem of linear track keeping for marine surface vessels. The influence exerted by sea currents on the kinematic equation of ships is considered first. The input-to-state stability(ISS) theory used to verify the system is input-to-state stable. Combining the Nussbaum gain with backstepping techniques,a robust adaptive fuzzy algorithm is presented by employing fuzzy systems as an approximator for unknown nonlinearities in the system. It is proved that the proposed algorithm that guarantees all signals in the closed-loop system are ultimately bounded. Consequently,a ship's linear track-keeping control can be implemented. Simulation results using Dalian maritime University's ocean-going training ship 'YULONG' are presented to validate the effectiveness of the proposed algorithm.

关键词： ISS theory adaptive control fuzzy system ship track-keeping

The Use of Hydrogen as a Fuel for Inland Waterway Units

在线全文

学校读者我要写书评

暂无评论

Journal of Marine Science and Application 2014年第2期13卷 212-217页

作者： M. Morsy El Gohary Yousri M. A. Welaya AmrAbdelwahabSaad Department of naval architecture and Marine Engineering Faculty of Engineering Alexandria University Egypt Marine Engineering Department Faculty of Maritime Studies King Abdulaziz University Jeddah Kingdom of Saudi Arabia

Escalating apprehension about the harmful effects of widespread use of conventional fossil fuels in the marine field and in internal combustion engines in general, has led to a vast amount of efforts and the directing of large capital investment towards research and development of sustainable alternative energy sources. One of the most promising and abundant of these sources is hydrogen. Firstly, the use of current fossil fuels is. discussed focusing on the emissions and economic sides to emphasize the need for a new, cleaner and renewable fuel with particular reference to hydrogen as a suitable possible alternative. Hydrogen properties, production and storage methods are then reviewed along with its suitability from the economical point of view. Finally, a cost analysis for the use of hydrogen in internal combustion engines is carried out to illustrate the benefits of its use as a replacement for diesel. The outcome of this cost analysis shows that 98% of the capital expenditure is consumed by the equipment, and 68.3% of the total cost of the equipment is spent on the solar photovoltaic cells. The hydrogen plant is classified as a large investment project because of its high initial cost which is about 1 billion US$; but this is justified because hydrogen is produced in a totally green way. When hydrogen is used as a fuel, no harmful emissions are obtained.

关键词： sustainable alternative energy sources hydrogen fuel hydrogen properties hydrogen production hydrogen storage costanalysis inland waterway units

NUMERICAL PREDICTION OF FATIGUE DAMAGE IN STEEL CATENARY RISER DUE TO VORTEX-INDUCED VIBRATION

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 154-163页

作者： GAO Yun ZONG Zhi SUN Lei State Key Laboratory of Structural Analysis for Industrial Equipment and Department of naval architecture and faculty of Vehicle Engineering and Mechanics Dalian University of Technology Dalian 116024 China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian116024 China faculty of Vehicle Engineering and Mechanics Dalian University of Technology Dalian 116024 China

For studying the characteristics of Steel Catenary Riser （SCR）, a simplified pinned-pinned cable model of vibration is established. The natural frequencies, the normalized mode shapes and mode curvatures of the SCR are calculated. The fatigue damage of the SCR can be obtained by applying the modal superposition method combined with the parameters of S -N curve. For analyzing the relation between the current velocity and the SCR＇s fatigue damage induced by the vortex-induced vibration, ten different current states are evaluated. Then, some useful conclusions are drawn, especially an important phenomenon is revealed that the maximum fatigue damage in the riser usually occurs near the area of the boundary ends.

关键词： vortex-induced vibration Steel Catenary Riser (SCR) fatigue damage modal superposition method