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Effects of the particle Stokes number on wind turbine airfoil erosion

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Applied Mathematics and Mechanics(English Edition) 2018年第5期39卷 639-652页

作者： Deshun LI Zhenxi ZHAO Yinran LI Qing WANG Rennian LI Ye LI College of Energy and Power engineering Lanzhou University of TechnologyLanzhou 730050China Gansu Provincial Technology Centre for Wind Turbines Lanzhou 730050China Gansu Provincial Key Laboratory of Fluid Machinery and Systems Lanzhou 730050China State Key Laboratory of Ocean engineering School of Naval ArchitectureOcean and CivilShanghai Jiao Tong UniversityShanghai 200240China

Under natural conditions, wind turbines are inevitably eroded by the action of sand-wind flow. To further investigate the effects of dust drift on the erosion of the wind turbine blades in sand-wind environments~ the effects of the wind velocity, particle diameter, and particle density on the erosion of wind turbine airfoils are studied, and the effects of the particle Stokes number on the airfoil erosion are discussed. The results show that, when the angle of attack （AOA） is 6.1~, there will be no erosion on the airfoil surface if the particle Stokes number is lower than 0.013 5, whereas erosion will occur if the particle Stokes number is higher than 0.015 1. Therefore, there exists a critical range for the particle Stokes number. When the particle Stokes number is higher than the maximum value in the critical range, airfoil erosion will occur. The result is further confirmed by changing the particle diameter, particle density, and inflow speed. It is shown that the erosion area on the airfoil and the maximum erosion rate are almost equal under the same particle Stokes number and AOA. The extent of airfoil erosion increases when the particle Stokes number increases, and the critical particle Stokes number increases when the AOA increases. Moreover, the geometric shape of the airfoil pressure surface greatly affects the airfoil erosion, especially at the curvature near the leading edge.

关键词： wind turbine airfoil erosion Stokes number sand-wind environment

Identification and distribution of 13003 landslides in the northwest margin of Qinghai-Tibet Plateau based on human-computer interaction remote sensing interpretation

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China Geology 2024年第2期7卷 171-187页

作者： Wei Wang Yuan-dong Huang Chong Xu Xiao-yi Shao Lei Li Li-ye Feng Hui-ran Gao Yu-long Cui Shuai Wu Zhi-qiang Yang Kai Ma National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China Key Laboratory of Compound and Chained Natural Hazards Dynamics Ministry of Emergency Management of Chin12eijing 100085China School of Emergency Management Science and engineering University of Chinese Academy of SciencesBeijing 100049China School of Soil and Water Conservation Beijing Forestry UniversityBeijing 100083China School of civil engineering and architecture Anhui University of Science and TechnologyHuainan 232001China No.3 Bureau of China Metallurgical Geology Bureau Taiyuan 030031China

The periphery of the Qinghai-Tibet Plateau is renowned for its susceptibility to ***,the northwestern margin of this region,characterised by limited human activities and challenging transportation,remains insufficiently explored concerning landslide occurrence and *** the planning and construction of the Xinjiang-Tibet Railway,a comprehensive investigation into disastrous landslides in this area is essential for effective disaster preparedness and mitigation *** using the human-computer interaction interpretation approach,the authors established a landslide database encompassing 13003 landslides,collectively spanning an area of 3351.24 km^(2)(36°N-40°N,73°E-78°E).The database incorporates diverse topographical and environmental parameters,including regional elevation,slope angle,slope aspect,distance to faults,distance to roads,distance to rivers,annual precipitation,and *** statistical characteristics of number and area of landslides,landslide number density(LND),and landslide area percentage(LAP)are *** authors found that a predominant concentration of landslide origins within high slope angle regions,with the highest incidence observed in intervals characterised by average slopes of 20°to 30°,maximum slope angle above 80°,along with orientations towards the north(N),northeast(NE),and southwest(SW).Additionally,elevations above 4.5 km,distance to rivers below 1 km,rainfall between 20-30 mm and 30-40 mm emerge as particularly susceptible to landslide *** study area’s geological composition primarily comprises Mesozoic and Upper Paleozoic *** fault and human engineering activities have different degrees of influence on landslide ***,the significance of the landslide database,the relationship between landslide distribution and environmental factors,and the geometric and morphological characteristics of landslides are *** landslide H/L ratios in the study area are

关键词： Landslides Human-computer interaction interpretation Landslide database Spatial distribution Earthquake Rainfall Human engineering activity Qinghai-Tibet Plateau Geological hazards survey engineering

Power Splitting Based SWIPT in Network-Coded Two-Way Networks with Data Rate Fairness:An Information-Theoretic Perspective

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China Communications 2016年第12期13卷 107-119页

作者： Ke Xiong Yu Zhang Yueyun Chen Xiaofei Di School of Computer and Information Technology Beijing Jiaotong University National Mobile Communications Research Laboratory Southeast University School of Computer and Communication engineering University of Science and Technology Beijing

This paper investigates the simultaneous wireless information and powertransfer(SWIPT) for network-coded two-way relay network from an information-theoretic perspective, where two sources exchange information via an SWIPT-aware energy harvesting(EH) relay. We present a power splitting(PS)-based two-way relaying(PS-TWR) protocol by employing the PS receiver architecture. To explore the system sum rate limit with data rate fairness, an optimization problem under total power constraint is formulated. Then, some explicit solutions are derived for the problem. Numerical results show that due to the path loss effect on energy transfer, with the same total available power, PS-TWR losses some system performance compared with traditional non-EH two-way relaying, where at relatively low and relatively high signalto-noise ratio(SNR), the performance loss is relatively small. Another observation is that, in relatively high SNR regime, PS-TWR outperforms time switching-based two-way relaying(TS-TWR) while in relatively low SNR regime TS-TWR outperforms PS-TWR. It is also shown that with individual available power at the two sources, PS-TWR outperforms TS-TWR in both relatively low and high SNR regimes.

关键词： two-way relay energy harvesting wireless power transfer data rate fairness network coding

APPLICATION OF WAVELET THEORY IN RESEARCHON WEIGHT FUNCTION OF MESHLESS METHOD

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Applied Mathematics and Mechanics(English Edition) 2005年第5期26卷 662-666页

作者：张红张选兵葛修润 School of Remote Sensing and Information engineering Wuhan UniversityWuhan 430079 P.R.China College of civil engineering and architecture Fuzhou UniversityFuzhou 350002 P.R.China Wuhan Institute of Rock and Soil Mechanics Chinese Academy of SciencesWuhan 430071 P.R.China

Multiresolution analysis of wavelet theory can give an effective way to describe the information at various levels of approximations or different resolutions, based on spline wavelet analysis,so weight function is orthonormally projected onto a sequence of closed spline subspaces, and is viewed at various levels of approximations or different resolutions. Now, the useful new way to research weight function is found, and the numerical result is given.

关键词： meshless method weight function spline wavelet multiresolution analysis

Vibration test of micro machined gyroscope based on high speed photography and SURF

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Journal of beijing Institute of Technology 2012年第2期21卷 179-184页

作者：姚峰林高世桥赵婕高崇仁 School of Mechatronical engineering Beijing Institute of Technology School of Mechanical engineering Taiyuan University of Science and Technology Computer engineering Department Taiyuan University

Based on three kinds of dynamic test of MEMS, a dynamic system for the vibration test of micro machined gyroscope based on high speed photography is introduced. Firstly, the architecture of the system hardware is introduced. Secondly, the image tracking performance is compared by the test using the template matching algorithm, the mean shift algorithm and the SURF algorithm. The vibration curve shows that high speed photograph combined with SURF algorithm is faster, more ac- curate, and more suitable for the vibration test of micro machined gyroscope. After the frequency a- nalysis and related interpolation, more characteristics of micro gyroscope can be obtained.

关键词： high speed photograph SURF micro machined gyroscope dynamic test vibration image

Extrapolation for Aeroengine Gas Path Faults with SVM Bases on Genetic Algorithm

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Sound & Vibration 2019年第5期53卷 237-243页

作者： Yixiong Yu School of Aeronautic Science and engineering Beihang UniversityBeijing100083China

Mining aeroengine operational data and developing fault diagnosis models for aeroengines are to avoid running aeroengines under undesired *** of the complexity of working environment and faults of aeroengines,it is unavoidable that the monitored parameters vary widely and possess larger noise *** paper reports the extrapolation of a diagnosis model for 20 gas path faults of a double-spool turbofan civil *** applying support vector machine(SVM)algorithm together with genetic algorithm(GA),the fault diagnosis model is obtained from the training set that was based on the deviations of the monitored parameters superimposed with the noise level of 10%.The SVM model(C=24.7034;γ=179.835)was extrapolated for the samples whose noise levels were larger than 10%.The accuracies of extrapolation for samples with the noise levels of 20%and 30%are 97%and 94%,*** with the models reported on the same faults,the extrapolation results of the GASVM model are accurate.

关键词： Aeroengine extrapolation gas path fault diagnosis genetic algorithm support vector machine

Adaptive mutation sparrow search algorithm-Elman-AdaBoost model for predicting the deformation of subway tunnels

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Underground Space 2024年第4期17卷 320-360页

作者： Xiangzhen Zhou Wei Hu Zhongyong Zhang Junneng Ye Chuang Zhao Xuecheng Bian MOE Key Laboratory of Soft Soils and Geoenvironmental engineering College of Civil Engineering and ArchitectureZhejiang UniversityHangzhou 310058China Hangzhou Canal Group Construction Management Co.LTD Hangzhou 310015China Ningbo Rail Transit Project Construction Headquarter Ningbo 315012China Center for Hypergravity Experimental and Interdisciplinary Research Zhejiang UniversityHangzhou 310058China

A novel coupled model integrating Elman-AdaBoost with adaptive mutation sparrow search algorithm(AM-SSA),called AMSSAElman-AdaBoost,is proposed for predicting the existing metro tunnel deformation induced by adjacent deep excavations in soft *** novelty is that the modified SSA proposes adaptive adjustment strategy to create a balance between the capacity of exploitation and *** AM-SSA,firstly,the population is initialized by cat mapping chaotic sequences to improve the ergodicity and randomness of the individual sparrow,enhancing the global search *** the individuals are adjusted by Tent chaotic disturbance and Cauchy mutation to avoid the population being too concentrated or scattered,expanding the local search ***,the adaptive producer-scrounger number adjustment formula is introduced to balance the ability to seek the global and local *** addition,it leads to the improved algorithm achieving a better accuracy level and convergence speed compared with the original *** demonstrate the effectiveness and reliability of AM-SSA,23 classical benchmark functions and 25 IEEE Congress on Evolutionary Computation benchmark test functions(CEC2005),are employed as the numerical examples and investigated in comparison with some wellknown optimization *** statistical results indicate the promising performance of AM-SSA in a variety of optimization with constrained and unknown search *** utilizing the AdaBoost algorithm,multiple sets of weak AMSSA-Elman predictor functions are restructured into one strong predictor by successive iterations for the tunnel deformation prediction ***,the on-site monitoring data acquired from a deep excavation project in Ningbo,China,were selected as the training and testing ***,the predictive outcomes are compared with those of other different optimization and machine learning *** the end,the obtained results in this real-world geotechnical eng

关键词： Adjacent deep excavations Existing subway tunnels Adaptive mutation sparrow search algorithm Metaheuristic optimization Benchmark test functions Elman neural networks

A smart assistance system for cable assembly by combining wearable augmented reality with portable visual inspection

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Virtual Reality & Intelligent Hardware 2020年第1期2卷 12-27页

作者： Lianyu ZHENG Xinyu LIU Zewu AN Shufei LI Renjie ZHANG School of Mechanical engineering and Automation Beihang UniversityBeijing 100191China

Background Assembly guided by paper documents is the most widespread type used in the process of aircraft cable *** process is very complicated and requires assembly workers with high-level *** technologies of wearable Augmented Reality(AR)and portable visual inspection can be exploited to improve the efficiency and the quality of cable *** In this study,we propose a smart assistance system for cable assembly that combines wearable AR with portable visual ***,a portable visual device based on binocular vision and deep learning is developed to realize fast detection and recognition of cable brackets that are installed on aircraft airframes.A Convolutional Neural Network(CNN)is then developed to read the texts on cables after images are acquired from the camera of the wearable AR *** authoring tool that was developed to create and manage the assembly process is proposed to realize visual guidance of the cable assembly process based on a wearable AR *** system is applied to cable assembly on an aircraft bulkhead *** The results show that this system can recognize the number,types,and locations of brackets,and can correctly read the text of aircraft *** authoring tool can assist users who lack professional programming experience in establishing a process plan,i.e.,assembly outline based on AR for cable *** The system can provide quick assembly guidance for aircraft cable with texts,images,and a 3 D *** is beneficial for reducing the dependency on paper documents,labor intensity,and the error rate.

关键词： Cable assembly Visual inspection Text reading Wearable AR Deep learning

DQN-Based Proactive Trajectory Planning of UAVs in Multi-Access Edge Computing

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Computers, Materials & Continua 2023年第3期74卷 4685-4702页

作者： Adil Khan Jinling Zhang Shabeer Ahmad Saifullah Memon Babar Hayat Ahsan Rafiq School of Electronic engineering Beijing University of Posts and TelecommunicationsBeijing100876China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing100876China Department of Automation Chongqing University of Posts and TelecommunicationsChongqing400065China

The main aim of future mobile networks is to provide secure,reliable,intelligent,and seamless *** also enables mobile network operators to ensure their customer’s a better quality of service(QoS).Nowadays,Unmanned Aerial Vehicles(UAVs)are a significant part of the mobile network due to their continuously growing use in various *** better coverage,cost-effective,and seamless service connectivity and provisioning,UAVs have emerged as the best choice for telco *** can be used as flying base stations,edge servers,and relay nodes in mobile *** the other side,Multi-access EdgeComputing(MEC)technology also emerged in the 5G network to provide a better quality of experience(QoE)to users with different QoS ***,UAVs in a mobile network for coverage enhancement and better QoS face several challenges such as trajectory designing,path planning,optimization,QoS assurance,mobilitymanagement,*** efficient and proactive path planning and optimization in a highly dynamic environment containing buildings and obstacles are ***,an automated Artificial Intelligence(AI)enabled QoSaware solution is needed for trajectory planning and ***,this work introduces a well-designed AI and MEC-enabled architecture for a UAVs-assisted future *** has an efficient Deep Reinforcement Learning(DRL)algorithm for real-time and proactive trajectory planning and *** also fulfills QoS-aware service provisioning.A greedypolicy approach is used to maximize the long-term reward for serving more users *** results reveal the superiority of the proposed DRL mechanism for energy-efficient and QoS-aware trajectory planning over the existing models.

关键词： Multi-access edge computing UAVs trajectory planning QoS assurance reinforcement learning deep Q network