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Impact of Stagger Angle Nonuniformity on Turbine Aerodynamic Performance

Journal of Thermal Science 2010年第5期19卷 465-472页

作者： Weihao Zhang Zhengping Zou Shangneng Pan Huoxing Liu Huoxing Liu Wei Li National Key Laboratory of Science and Technology on Aero-Engines School of Jet Propulsion Beihang University Beijing 100191 China Aeroengine Numerical Simulation Research Center B eihang University Beijing 100191 China Chinese Aviation Powerplant Research Institute Zhuzhou 412002 China

The assembling error may lead to variation in stagger angles,which would affect the aerodynamic performance of the *** investigate this underlying effect,two parallel numerical experiments on two turbines with the same profile,but uniform and nonuniform vane stagger angle respectively,were conducted in both steady and unsteady *** results indicate that certain changes in the detailed flow field of the turbine occur when the stagger angles are nonuniform,further,the blade loading distribution of the vane and rotor become markedly different from that in uniform vane stagger angle *** these consequences caused by nonuniformity mentioned above enhance the unsteadiness of the flow,finally,the aerodynamic performance changes *** also shows that,compared with steady simulation,the unsteady numerical simulation is necessary in this investigation.

关键词： assembling error stagger angle nonuniformity turbine aerodynamic performance

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Visualization of signalized intersections in driving simulator and validity of driving behaviors in virtual environments

Advances in Transportation Studies

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Advances in Transportation Studies 2011年第26期 17-28页

作者： Yan, X. Abdel-Aty, M. Guo, D. Radwan, E. MOE Key Laboratory for Transportation Complex Systems Theory and Technology Beijing Jiaotong University Beijing 100044 China Department of Civil and Environmental Engineering University of Central Florida Orlando FL 32816-2450 United States Computer Science Program College of Business Florida Gulf Coast University 10501 FGCU Boulevard South Fort Myers FL 33965-6565 United States Center for Advanced Transportation Systems Simulation University of Central Florida Orlando FL 32816-2450 United States

Visualization of highway traffic environments in virtual reality plays a key role on fidelity of simulation and validity of driving behaviors in driving simulator studies. This paper describes a procedure to replicate a signalized intersection with many complex features into a driving simulator's 3-D databases through building a graphical visual database, constructing a road motion database, and creating simulated traffic. The validity of the visualization was assessed via the comparison of the drivers' speeds in the simulator and the speed data at the real intersection. It was found that both speed data follow normal distributions and have equal means for each intersection approach;however, that the speeds measured in the driving simulator have a larger variability than those measured in the field. The users' subjective evaluation results indicated that 92% subjects could recognize the simulated intersection in the driving simulator experiment. Therefore, the strategy of geo-specific environment modeling would be useful for studying driving behaviors in virtual environments.

关键词： Visualization

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Object tracking based on local feature points

Object tracking based on local feature points

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Congress on Image and Signal Processing, CISP

作者： Haili Wang Liang Zhang Training Center of Engineering Technology Civil Aviation University of China Tianjin China Tianjin Key Laboratory for Advanced Signal Processing Civil Aviation University of China Tianjin China

This paper presents a novel local-feature-based algorithm to track objects through frames. Real-time performance and occlusion are great challenges in object tracking. Local features are more distinctive than global features in dealing with occlusion. SURF (Speeded-Up Robust Feature) can robustly identify objects in clutter scene and occlusion. However, initial SURF algorithm has difficulty in matching accurately. Combined NN/SN (ratio of closest and next closes distances) with RANSAC (Random Sample Consensus) algorithm and location correlation of corresponding features between two frames is proposed to reduce false match and speed up the matching procedure. This method exhibits very good performance in high reliable applications, for its effectiveness and reduced complexity. simulation on PETS database proves it effective.

关键词： Artificial neural networks Tin Feature extraction Signal processing algorithms Correlation Robustness Computer vision

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Researches on modeling and simulation of turbo-shaft engine and main rotor system

Researches on modeling and simulation of turbo-shaft engine ...

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2009 WRI World Congress on Computer Science and Information Engineering, CSIE 2009

作者： Ma, Shi-Dong Han, Liang Gong, Guang-Hong Song, Xiao Aviation Key Laboratory for Advanced Simulation Technology Beijing University of Aeronautics and Astronautics Beijing 100191 China

ISBN: (纸本)9780769535074

Modeling of power system plays an important part in modeling of helicopter dynamics system. The precision of turbo-shaft engine model affects directly the fidelity of power system model in process of modeling and simulation on helicopter. Modeling techniques of turbo-shaft engine are studied first, secondly, engine control system model based on main rotor load feedback is proposed and an inner-outer series-wound control loop to adjust engine output power based on feedback control is developed. The control law of turbo-shaft engine power adjustment is designed. Consequently, integrative model of turboshaft engine and main rotor on helicopter power system is realized. A simulation example for helicopter power system is given in this paper to validate the integrative model. © 2008 IEEE.

关键词： Helicopters

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Researches on Modeling and simulation of Turbo-Shaft Engine and Main Rotor System

Researches on Modeling and Simulation of Turbo-Shaft Engine ...

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Computer Science and Information Engineering, CSIE, WRI World Congress on FLAGGED

作者： Ma Shi-dong Han Liang Gong Guang-hong Song Xiao Aviation Key Laboratory of Advanced Simulation Technology Beijing Aeronautics and Astronautics University Beijing China

Modeling of power system plays an important part in modeling of helicopter dynamics system. The precision of turbo-shaft engine model affects directly the fidelity of power system model in process of modeling and simulation on helicopter. Modeling techniques of turbo-shaft engine are studied first, secondly, engine control system model based on main rotor load feedback is proposed and an inner-outer series-wound control loop to adjust engine output power based on feedback control is developed. The control law of turbo-shaft engine power adjustment is designed. Consequently, integrative model of turbo-shaft engine and main rotor on helicopter power system is realized. A simulation example for helicopter power system is given in this paper to validate the integrative model.

关键词： Engines Power system modeling Power system simulation Power system dynamics Helicopters Control system synthesis Output feedback Feedback loop Power generation Feedback control

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Structure of large gold clusters obtained by global optimization using the minima hopping method

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Physical Review B 2009年第4期79卷 041405(R)-041405(R)页

作者： Kuo Bao Stefan Goedecker Kenji Koga Frédéric Lançon Alexey Neelov State Key Laboratory of Superhard Materials Jilin University Changchun 130012 China Department of Physics Universität Basel Klingelbergstrasse 82 4056 Basel Switzerland National Institute of Advanced Industrial Science and Technology (AIST) Tsukuba Ibaraki 305-8565 Japan INAC SP2M Laboratoire de Simulation Atomistique (L_Sim) CEA F-38054 Grenoble France

The energetic ground state of gold clusters with up to 318 atoms consists of complex geometries that have only a limited resemblance to the perfect icosahedra, decahedra, and octahedra that are encountered for some magic numbers. The structure changes in most cases completely by the addition of a single atom. Other low-energy structures are so close in energy that their Boltzmann weight is not negligible at room temperature.

关键词： gold ground states metal clusters

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Traction control methods based on special off-road vehicle with power take-off

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Jilin Daxue Xuebao (Gongxueban)/Journal of Jilin University (Engineering and technology Edition) 2009年第SUPPL. 1期39卷 18-21页

作者： Gao, Yang Li, Jing Lei, Yu-Long Gu, Ming-Qi Liu, Xue-Wei Li, You-De State Key Laboratory of Automobile Dynamic Simulation Jilin University Changchun 130022 China China Sanjiang Space Group in the Special Vehicle Technology Center Wuhan 430023 China Aviation University of Air Forces Changchun 130022 China

Traction control methods of special off-road vehicle with the power take-off were analyzed. The traction control strategy on the low attachment coefficient road relying on adjusting the clutch, axle differential and brake was presented. A full-time four-wheel-drive special off-road vehicle model with clutch was established. A software in-the-loop simulation platform with MATLAB was built and the simulation was analyzed. The results show that the traction control methods of special off-road vehicle with the power take-off can control the slip rate of over-spin wheels at the best value range without adjusting engine throttle, therefore the vehicle can pass the low adhesion road region.

关键词： Traction control

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Ordered structures of rhombohedral system

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Chinese Science Bulletin 2008年第4期53卷 534-539页

作者： SONG QingGong JIANG EnYong Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology and Institute of Advanced Materials Physics Faculty of Science Tianjin University Tianjin 300072 China Department of Materials Physics College of Science Civil Aviation University of China Tianjin 300300 China

Lattice gas model is presented for rhombohedral *** ordered structure types and four perfectly ordered structures are determined using concentration wave *** ordered structures of cation in corundum-type dimetal triox... 详细信息

关键词：斜方六面体结构菱形晶体刚玉规则结构

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Military task programming based on finite state machine (FSM) decision-making model

Military task programming based on finite state machine (FSM...

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International Conference on System simulation and Scientific Computing, ICSC

作者： Shidong Ma Guanghong Gong Liang Han Xiao Song The Aviation Key Laboratory for Advanced Simulation Technology Beijing Aeronautics and Astronautics University Beijing China The School of Automation Science and Electrical Engineering Beijing Aeronautics and Astronautics University Beijing China

Military task programming is an important foundation in military warfare simulations. Presently, scenarios in joint military warfare are built not so good to meet the requirement of aggregate-level warfare simulations and the requirement of intelligent decision in real time simulations. A method based on FSM model of aggregate-level military warfare decision-making and vehicle-level action decision-making is proposed in this paper. The programming process of joint military warfare with decision-making functions can be realized through the programming of these two levels, and the dynamic decision-making and execution of mission can be completed successfully.

关键词： Automata Decision making Military computing Dynamic programming Computational modeling Machine intelligence Functional programming Vehicle dynamics Computer simulation Space missions

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SSB: A grid-based infrastructure for HLA systems 06

SSB: A grid-based infrastructure for HLA systems

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6th IEEE International Symposium on Cluster Computing and the Grid, 2006. CCGRID 06

作者： Xu, Li-Juan Peng, Xiao-Yuan Advanced Simulation Technology Aviation Science and Technology Key Laboratory Beihang University

ISBN: (纸本)0769525857

Service Oriented EXtensible Modeling and simulation Supporting Environment Architecture (SO-XMSSEA) is presented based on XMSF thinking and the new technology development of web service and grid. simulation Service Bus (SSB) is the underlying infrastructure to take charge of services communicating in SO-XMSSEA including message dispatch, integration, services interaction, management with services quality and security, and adaptation with other domain applications. We introduce the main mechanism of SSB structure and survey the communication and data transferring between clients and server. As the most important approach for composing HLA systems, the core module of SO-RTI Server and System Integration Server are discussed in detail. WSRF based grid technology is selected to construct prototype SSB implementation. A test HLA system based on SSB shows the interoperability on heterogeneous systems so that different types of systems can communicate smoothly through WAN and makes more facility to maintain and evolve. © 2006 IEEE.

关键词： Parallel processing systems

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