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Energy Harvesting in the Wake of An Inverted C-Shaped Bluff Body

China Ocean Engineering 2024年第1期38卷 68-80页

作者： WANG Jun-lei li shen-fang Md.Mahbub ALAM ZHU Hong-jun HU Guo-biao School of Mechanical and Power Engineering Zhengzhou UniversityZhengzhou 450000China Center for Turbulence Control Harbin Institute of Technology(Shenzhen)Shenzhen 518055China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500China Internet of Things Thrust The Hong Kong University of Science and Technology(Guangzhou)Guangzhou 511400China

This paper proposes a novel wake-induced vibration(WIV)-based energy harvesting system consisting of two bluff *** inverted C-shaped bluff body is stationary installed at the upstream position to generate an interference wake street,and a cylinder bluff body equipped with a transducer is elastically suspended at the downstream position to harness WIV *** hydrodynamics and energy harvesting(EH)performance of the proposed system are investigated via experimental *** reduced velocity(U*)ranging from 2 to 14(the corresponding Reynolds number ranging from 15100 to 106200)is considered in the present *** is found that the wake generated by the inverted C-shaped bluff body significantly affects the EH *** the opening angle(α)of the C-shaped bluff body increases the vibration amplitude of the downstream cylinder,thereby increasing the harvested *** the spacing(L)between two bluff bodies is two times the cylinder diameter(D),the wake-induced vibration(WIV)mode is observed,while the combined WIV and wake galloping(WG)mode occurs whenαis 150°,and L equals 3D or *** average drag coefficient becomes negative when L is 2D,3D,or *** carefully configuring a C-shaped bluff body,the wake generated by it can bring an augmenting effect on the vibration of the downstream EH *** example,the RMS power output of the proposed EH system reaches a maximum of 0.31 W at U*=8 and L=4D,which is 300%greater than that of its traditional ***,after a number of case stud-ies,it is identified that the proposed EH system can achieve the best performance whenαis 150°and L=2D.

关键词： wake-induced vibration vortex-induced vibration galloping energy harvesting bluff body

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基于PEEC的WPT系统磁芯结构建模

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电力电子技术 2024年第3期58卷 78-80,117页

作者：许肖颖夏能弘张帆李方深上海电力大学电气工程学院上海200090 国网安徽省电力公司安徽合肥230000

磁耦合机构作为无线电能传输的核心部分,直接决定系统的传输性能。目前广泛采用加装磁芯来提高耦合机构的传输性能。然而加入磁芯后,线圈与磁芯的融合建模及协同设计问题,目前多依赖于电磁仿真软件及二维分区建模,该方法无法量化磁芯参... 详细信息

磁耦合机构作为无线电能传输的核心部分,直接决定系统的传输性能。目前广泛采用加装磁芯来提高耦合机构的传输性能。然而加入磁芯后,线圈与磁芯的融合建模及协同设计问题,目前多依赖于电磁仿真软件及二维分区建模,该方法无法量化磁芯参数对系统传输性能的作用。此处基于部分元等效电路(PEEC)对磁芯进行建模,根据磁性材料特性分别从涡流、磁化强度两方面构建磁芯二元模型,并引入退磁因子对磁化强度模型进行修正。基于电场积分方程构建了以磁芯涡流、节点电压和磁化强度为未知量的解决矩阵,实现了线圈与磁芯融合建模。在融合建模的基础上,基于矢量磁位提取了带芯线圈的自感系数,将建模结果与商用仿真软件及实验进行对比,其误差控制在5%以内,验证了建模结果的准确性。带芯线圈自感参数量化了磁芯对线圈的附加耦合作用,为磁芯结构设计提供理论支撑。

关键词：无线电能传输部分元等效电路自感系数

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Stability Investigation and Improvement for DC Cascade Systems with Simplified Impedance-based Stability Criterion

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1044-1052页

作者： Junbin fang Zhikang Shuai Yang li Zhibing Wang Xiangyang Wu Xia shen Z.John shen College of Electrical and Information Engineering Hunan UniversityChangsha 410082China Renewable Energy Department of China Electric Power Research Institute Beijing 100192China Department of Electrical and Computer Engineering Illinois Institute of TechnologyChicagoIL 60616USA IEEE

In DC distributed power systems(DPSs),the complex impedance interactions possibly lead to DC bus voltage oscillation or *** previous research,the stability analysis of DPSs is implemented based on mathematical analysis in control *** specific mechanisms of the instability of the cascade system have not been intuitively *** this paper,the stability analysis of DPSs based on the traditional Nyquist criterion is simplified to the resonance analysis of the seriesconnected port impedance(Z=R+jX)of source and load *** reveals that the essential reason for impedance instability of a DC cascade system is that the negative damping characteristic(Rlifies the internal resonance source at reactance zero-crossing *** simplified stability criterion for DC cascade systems can be concluded as:in the negative damping frequency ranges(Rlity criterion,the oscillation modes of cascade systems are classified.A typical one is the internal impedance instability excited by the negative damping,and the other one is that the external disturbance amplified by negativity in a low stability ***,the impedance reshaping method for stability improvement of the system can be further *** validity of the simplified criterion is verified theoretically and experimentally by a positive damping reshaping method.

关键词： DC cascaded system,impedance model impedance reconstruction stability criterion

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Constitutive modelling of concrete material subjected to low-velocity projectile impact:insights into damage mechanism and target resistance

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第2期25卷 161-182页

作者： shen liU Xieping HUANG Xiangzhen KONG Qin fang Center for Hypergravity Experiment and Interdisciplinary Research Zhejiang UniversityHangzhou310058China Institute of Geotechnical Engineering Zhejiang UniversityHangzhou310058China State Key Laboratory of Disaster Prevention&Mitigation of Explosion&Impact Army Engineering University of PLANanjing210007China

This paper presents a numerical study to improve the understanding of the complex subject of penetration and perforation of concrete targets impacted by low-velocity *** main focus is on the damage mechanisms and the major factors that account for the target resistance of the *** improved continuous surface cap model recently proposed was *** model was first equipped with element erosion criteria and was adequately validated by comparisons with ballistic *** numerical simulations were carried out where the individual influence of tensile,shear,and volumetric behaviors(pore collapse)of a concrete target on its ballistic performance was *** demonstrated that cratering on the front face and scabbing on the rear face of the concrete target were mainly dominated by its tensile *** major target resistance came from the second tunneling stage which was primarily governed by the shear and volumetric behaviors of the ***,this study captured the pore collapse-induced damage phenomenon during the high-pressure tunneling stage,which has been extensively reported in experiments but has usually been neglected in previous numerical investigations.

关键词： Penetration Perforation Damage mechanism Target resistance Projectile impact Pore collapse

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Fast prototype and rapid construction of three-dimensional and multi-scaled pitcher for controlled drainage by systematic biomimicry

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International Journal of Extreme Manufacturing 2024年第3期6卷 489-503页

作者： Tao shen Ning li Shijie liu Cunlong Yu Chengqi Zhang Kang Yang Xingfei li Ruochen fang Lei Jiang Zhichao Dong Research Institute for Frontier Science Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education BeijingSchool of ChemistryBeihang UniversityBeijing 100191People’s Republic of China CAS Key Laboratory of Bio-inspired Materials and Interfacial Science Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190People’s Republic of China CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 100083People’s Republic of China School of Future Technology&School of Nanoscience and Engineering University of Chinese Academy of SciencesBeijing 101407People’s Republic of China School of Chemistry and Materials Science University of Science and Technology of China230026 HefeiAnhuiPeople’s Republic of China Suzhou Institute for Advanced Research University of Science and Technology of China215123 SuzhouJiangsuPeople’s Republic of China State Key Laboratory of Precision Measuring Technology and Instruments Tianjin University300072 TianjinPeople’s Republic of China

Biomimetic materials that use natural wisdom to solve practical problems are developing *** trend for systematic biomimicry is towards in-situ characterization of naturalcreatures with high spatial ***,rapid reconstruction of digital twin models with the same complex features as the prototype is ***,it faces bottlenecks and limits in fast characterization and fabrication,precise parameter optimization,geometricdeviations control,and quality *** solve these challenges,here,we demonstrate astate-of-the-art method taking advantage of micro-computed tomography and three-dimensional printing for the fast characterization of the pitcher plant Nepenthes x ventrata and fabrication of its biomimetic model to obtain a superior drainage controller with multiscale structures withprecise surface morphology optimization and geometric deviation ***-rupture-based drainage dynamic and mechanisms are characterized by x-ray and high-speed videography,which determines the crucial structures for unique *** the optimized artificial pitchers are further developed into sustained drainage devices with novel applications,such as detection,reaction,and smoke control.

关键词： systematic biomimicry biomimetic materials Micro-CT drainage digital twin

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Timing effect of high temperature exposure on the plasticity of internode and plant architecture in maize

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Journal of Integrative Agriculture 2024年第2期23卷 551-565页

作者： Binbin li Xianmin Chen Tao Deng Xue Zhao fang li Bingchao Zhang Xin Wang Si shen Shunli Zhou College of Agronomy and Biotechnology China Agricultural UniversityBeijing 100193China China Tobacco Hunan Industrial Corporation Changsha 410019China Innovation Center of Agricultural Technology for Lowland Plain of Hebei Wuqiao 061802China

The occurrence of high temperature(HT)in crop production is becoming more frequent and unpredictable with global warming,severely threatening food *** state of an organ’s growth and development is largely determined by the temperature conditions it is exposed to over *** is the main cereal crop,and its stem growth and plant architecture are closely related to lodging resistance,and especially sensitive to ***,systematic research on the timing effect of HT on the sequentially developing internode and stem is currently *** identify the timing effect of HT on the morphology and plasticity of the stem in maize,two hybrids(Zhengdan 958(ZD958),Xianyu 335(XY335))characterized by distinct morphological traits in the stem were exposed to a 7-day HT treatment from the V6 to V17 stages(Vn presents the vegetative stage with n leaves fully expanded)in *** results demonstrated that exposure to HT during V6-V12 accelerated the rapid elongation of *** instance,HT occurring at V7 and V12 specifically promoted the lengths and weights of the 3rd-5th and 9th-11th internodes,***,HT slowed the growth of internodes adjacent to the promoted ***,compared with control,the plant height was significantly increased soon after HT treatment,but the promotion effect became narrower at the subsequent flowering stage,demonstrating a self-adjusting mechanism in the maize plant in response to ***,HT altered the plant architectures,including a rising of the ear position and increase in the ear position ***335 exhibited greater sensitivity in stem development than ZD958 under HT *** findings improve our systematic understanding of the plasticity of internode and plant architecture in response to the timing of HT exposure.

关键词： maize high temperature internode growth plasticity plant architecture

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THE CALCULATION OF THE PROFILE-liNEAR AVERAGE VELOCITY IN THE TRANSITION REGION FOR ULTRASONIC HEAT METER BASED ON THE METHOD OF LES

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Journal of Hydrodynamics 2011年第1期23卷 89-94页

作者： liU Yong-hui DU Guang-sheng TAO li-li shen fang School of Energy and Power Engineering Shandong University Jinan 250061 China

The measurement accuracy of an ultrasonic heat meter depends on the relationship of the profile-linear average *** are various methods for the calculation of the laminar and turbulence flow regions,but few methods for the transition *** present,the traditional method to deal with the transition region is to adopt the relationship for the turbulent flow *** this article,a simplified model of the pipe is used to study the characteristics of the transition flow with specific Reynolds *** k-εmodel and the Large Eddy Simulation（LES）model are,respectively,used to calculate the flow field of the transition region,and a comparison with the experiment results shows that the LES model is more effective than the k-εmodel,it is also shown that there will be a large error if the relationship based on the turbulence flow is used to calculate the profile-linear average velocity relationship of the transition *** profile-linear average velocity for the Reynolds number ranging from 5 300 to 10 000 are calculated,and the relationship curve is *** results of this article can be used to improve the measurement accuracy of ultrasonic heat meter and provide a theoretical basis for the research of the whole transition flow.

关键词： ultrasonic heat meter Large Eddy Simulation(LES) model profile average velocity linear average velocity pipe

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Theoretical Analysis of Cooperative Driving at Idealized Unsignalized Intersections

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Tsinghua Science and Technology 2024年第1期29卷 257-270页

作者： shen li Jiawei Zhang Zhenwu Chen li li Department of Civil Engineering Tsinghua UniversityBeijing 100084China Department of Automation Tsinghua UniversityBeijing 100084China shenzhen Urban Transport Planning Center Co. Ltd.Shenzhen 518000China

Cooperative driving is widely viewed as a promising method to better utilize limited road resources and alleviate traffic *** recent years,several cooperative driving approaches for idealized traffic scenarios(i.e.,uniform vehicle arrivals,lengths,and speeds)have been ***,theoretical analyses and comparisons of these approaches are *** this study,we propose a unified group-by-group zipper-style movement model to describe different approaches synthetically and evaluate their *** derive the maximum throughput for cooperative driving plans of idealized unsignalized intersections and discuss how to minimize the delay of *** obtained conclusions shed light on future cooperative driving studies.

关键词： cooperative driving connected and automated vehicles unsignalized intersection

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Auto-parametric resonance of a continuous-beam-bridge model under two-point periodic excitation:an experimental investigation and stability analysis

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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 445-454页

作者： li Yuchun shen Chao liu Wei li Dong Department of Hydraulic Engineering College of Civil EngineeringTongji UniversityShanghai 200092China

The auto-parametric resonance of a continuous-beam bridge model subjected to a two-point periodic excitation is experimentally and numerically investigated in this *** auto-parametric resonance experiment of the test model is conducted to observe and measure the auto-parametric resonance of a continuous beam under a two-point excitation on *** parametric vibration equation is established for the test model using the finite-element *** auto-parametric resonance stability of the structure is analyzed by using Newmark's method and the energy-growth exponent *** effects of the phase difference of the two-point excitation on the stability boundaries of auto-parametric resonance are studied for the test *** with the experiment,the numerical instability predictions of auto-parametric resonance are consistent with the test phenomena,and the numerical stability boundaries of auto-parametric resonance agree with the experimental *** a continuous beam bridge,when the ratio of multipoint excitation frequency(applied to the columns)to natural frequency of the continuous girder is approximately equal to 2,the continuous beam may undergo a strong auto-parametric *** with the present experiment and analysis,a hypothesis of Volgograd Bridge's serpentine vibration is discussed.

关键词： auto-parametric resonance continuous beam bridge model two-point excitation experimental investigation stability analysis vibration of Volgograd Bridge

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Robust tantalum tuned perovskite oxygen electrode for reversible protonic ceramic electrochemical cells

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Rare Metals 2024年第7期43卷 3055-3065页

作者： Yu-Shi Feng Yu shen fang Wang Chuan Tian Qin-Yi Hu Qian Duan Jing-Wei li Di Bao School of Materials Science and Engineering Changchun University of Science and Technology Zhongshan Institute of Changchun University of Science and Technology State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of Sciences Key Laboratory of Preparation and Applications of Environmental Friendly Materials Ministry of EducationJilin Normal University

Perovskite oxides with diverse composition and structure have exhibited grand advances in boosting the oxygen reduction and evolution reaction（ORR/OER）,which are essential for the reversible protonic ceramic electrochemical cell（R-PCEC） toward the sustainable hydrogen production and ***,enhancement of their activity and stability remains ***,we develop the Ta-regulated BaCo0.7Fe0.3O3-δperovskite oxygen electrode(Ba(Co0.7Fe0.3)1-xTaxO3-δ)with abundant oxygen defects and achieve the simultaneous enhancement in the electrocatalytic activity and stability toward ORR and ***-fabricated R-PCEC with(Ba(Co0.7Fe0.3)0.9Ta0.1O3-δ)（BCFT10） oxygen electrode performs high power density of 1.47 W·cm-2at 650℃ in fuel cell mode,and the current density is up to-2.11 A·cm-2at 1.4 V at 650℃ in electrolysis mode,as well as the good stability in both the fuel cell and electrolysis ***,the cell also demonstrates a stable cycling operation between fuel cell and electrolysis mode,suggesting a great potential of BCFT10 as oxygen electrode material for R-PCECs.

关键词： Reversible protonic ceramic electrochemical cells Perovskite oxide Oxygen electrode Ta element doping Oxygen defects

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