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Chinese Journal of Aeronautics 2020年第1期33卷 149-160页

作者： Xiutao bian Qingsong WANG Xinrong SU Xin YUAN Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua UniversityBeijing 100084China

Accurate predictions of Shock Waves and Boundary Layer Interaction(SWBLI)and strong Shock Waves and Wake Vortices Interaction(SWWVI)in a highly-loaded turbine propose challenges to the currently widely used Reynolds-Averaged Navier-Stokes(RANS)*** this work,the SWBLI and the SWWVI in a highly-loaded Nozzle Guide Vane(NGV)are studied using a hybrid RANS/LES *** Turbulence Kinetic Energy(TKE)budget and the Proper Orthogonal Decomposition(POD)method are used to analyze flow *** show that this hybrid RANS/LES method can obtain detailed flow structures for flow mechanisms *** shock waves induce boundary layer separation,while the presence of a separation bubble can in turn lead to a Mach reflection *** shock waves cause trailing-edge vortices to break clearly,and the wakes,in turn,can change the shocks intensity and ***,the Entropy Generation Rate(EGR)is used to analyze the irreversible *** turns out that the SWWVI can reduce the flow field *** are several weak shock waves in the NGV flow field,which can increase the irreversible *** work offers flow mechanisms analysis and presents the EGR distribution in SWBLI and SWWVI areas in a transonic turbine blade.

关键词： Boundary layer Hybrid RANS/LES NGV Shock waves Wakes

Assessment of future climate change impacts on water-heat-salt migration in unsaturated frozen soil using CoupModel

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Frontiers of Environmental Science & Engineering 2021年第1期15卷 145-161页

作者： Hanli Wan Jianmin bian Han Zhang Yihan Li College of New Energy and Environment Jilin UniversityChangchun 130021China Key Laboratory of Groundwater Resources and Environment(Ministry of Education) Jilin UniversityChangchun 130021China

The transport mechanisms of water,heat,and salt in unsaturated frozen soil,as well as its response to future climate change are in urgent need of *** this study,western Jilin Province in north-eastern China was studied to produce a model of coupled water-heat-salt in unsaturated frozen soil using *** water,heat,and salt dynamics of unsaturated frozen soil under three representative concentration pathway(RCP)scenarios were simulated to analyze the effects of future climate change on unsaturated frozen *** results show that water,heat,and salt migration are tightly coupled,and the soil salt concentration in the surface layer(10 cm)exhibits explosive growth after freezing and *** future(2020–2099)meteorological factors in the study area were predicted using the Statistical Downscaling Model(SDSM).For RCP2.6,RCP4.5,and RCP8.5 scenarios,future temperatures during the freeze–thaw period increased by 2.68°C,3.18°C,and 4.28°C,respectively;precipitation increased by 30.28 mm,28.41 mm,and 32.17 mm,respectively;and evaporation increased by 93.57 mm,106.95 mm,and 130.57 mm,*** change will shorten the freeze–thaw period,advance the soil melting time from April to March,and enhance water and salt *** to the baseline period(1961–2005),future soil salt concentrations at 10 cm increased by 1547.54 mg/L,1762.86 mg/L,and 1713.66 mg/L under RCP2.6,RCP4.5,and RCP8.5,*** explosive salt accumulation is more *** measures should be taken to prevent the salinization of unsaturated frozen soils and address climate change.

关键词： Soil salinization Climate change Unsaturated frozen soil Water-heat-salt balance Soil environment change

On the robustness of median sampling in noisy evolutionary optimization

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Science China(Information Sciences) 2021年第5期64卷 32-44页

作者： Chao bian Chao QIAN Yang YU Ke TANG State Key Laboratory for Novel Software Technology Nanjing University Shenzhen Key Laboratory of Computational Intelligence Department of Computer Science and EngineeringSouthern University of Science and Technology

Evolutionary algorithms(EAs) are a sort of nature-inspired metaheuristics, which have wide applications in various practical optimization problems. In these problems, objective evaluations are usually inaccurate, because noise is almost inevitable in real world, and it is a crucial issue to weaken the negative effect caused by noise. Sampling is a popular strategy, which evaluates the objective a couple of times, and employs the mean of these evaluation results as an estimate of the objective value. In this work, we introduce a novel sampling method, median sampling, into EAs, and illustrate its properties and usefulness theoretically by solving OneMax, the problem of maximizing the number of 1 s in a bit string. Instead of the mean, median sampling employs the median of the evaluation results as an estimate. Through rigorous theoretical analysis on OneMax under the commonly used onebit noise, we show that median sampling reduces the expected runtime exponentially. Next, through two special noise models, we show that when the 2-quantile of the noisy fitness increases with the true fitness, median sampling can be better than mean sampling; otherwise,it may fail and mean sampling can be better. The results may guide us to employ median sampling properly in practical applications.

关键词： evolutionary algorithms noisy optimization median sampling computational complexity runtime analysis

A Four-legged Wall-climbing Robot with Spines and Miniature Setae Array Inspired by Longicorn and Gecko

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Journal of Bionic Engineering 2021年第2期18卷 292-305页

作者： Shiyuan bian Yuliang Wei Feng Xu Deyi Kong Institute of Intelligent Machines Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230009China

In industrial applications,climbing robots are widely used for climbing and detection of rough or smooth pipe *** by the special claws of longicorn is that can crawl on rough surfaces and the array of tiny bristles of geckos that can crawl on smooth surfaces,a new type of wall-climbing robot for rough or smooth surfaces is proposed in this *** bionic palms of the robot are suggested with special bionic hooks inspired by the longicorn and bionic adhesive materials inspired by the gecko with a good performance on adhering on the *** special bionic hooks are manufactured by the 3D printing method and the bionic adhesive materials are made by the polymer print lithography *** two different bionic adhere accessory are used on the robot’s palm to achieve climbing on the different *** foldable climbing robot can not only bend its own body to accommodate the cylindrical contact surfaces of different diameters,but also crawl on vertical rough and smooth surfaces using their bionic palms.

关键词： wall-climbing robot miniature setae array bionic hooks bionic palms bionic adhesive materials

Noise Reduction of UAV Using Biomimetic Propellers with Varied Morphologies Leading-edge Serration

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Journal of Bionic Engineering 2020年第4期17卷 767-779页

作者： Yuliang Wei Feng Xu Shiyuan bian Deyi Kong State Key Laboratory of Transducer Technology Key Laboratory of Biomimetic Sensing and Advanced Robot Technology of Anhui ProvinceInstitute of Intelligent MachinesChinese Academy of SciencesHefei 230031China Science Island Branch of Graduate School University of Science and Technology of ChinaHefei 230009China

The Leading-Edge(LE)serrations on owls'wings are known to be responsible for silent ***,this design has rarely been applied to reduce the noise of rotational rotor propellers and the morphologies of the existing serration designs are ***,we present a comparative study ofLE serrations with different morphologies in terms of the effectiveness in suppressing noise and promoting thrust *** performances of biomimetic propellers are investigated by Computational Fluid Dynamics(CFD)simulations and rotation *** simulation results reveal that LE serrations could reduce velocity fluctuations and change the lamina-turbulent transition and turbulence distribution on the suction surface of propeller,but the morphology of the serrations influences its *** testing results indicate that the sawtooth propeller has the best performance on noise reduction(on average 2.43 dB and in maximum 4.18 dB)and simultaneously enhancing the thrust forces(3.53%).The largest practical noise reductions(4.73 dB and 3.79 rdB)using the sawtooth propeller are observed when the quad-rotor Unmanned-Aerial Vehicle(UAV)is hovering at heights of 5 m and 8 m,*** results indicate the robustness and usefulness of owl-inspired biomimetic serration devices for aero-acoustic control and aerodynamic performance promotion on propeller *** finding is expected to con^bute to suppressing the sound of propeller and the rotor-based aircraft.

关键词： unmanned-aerial vehicle biomimetic noise reduction LE serration rotor propeller

Performance Analysis and Flexible Control of a Novel Ball Double-screw Hydraulic Robot Knee Joint

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Journal of Bionic Engineering 2023年第5期20卷 2147-2163页

作者： Jie Shao Yongming bian Meng Yang Guangjun Liu School of Mechanical Engineering Tongji UniversityShanghai201804China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou310027China Department of Control Science and Engineering Tongji UniversityShanghai201804China National Engineering Technology Research Center for Prefabrication Construction in Civil Engineering Tongji UniversityShanghai200092China

Focusing on the ball double-screw hydraulic knee joint as the research object,this paper analyzes the load driving performance of the hydraulic knee *** the posture data of the human body such as walking,squatting and landing buffer as initial learning objects,motion features are *** simplifying the trajectories of different motion actions into key feature control points and flexible trajectory fitting,the trajectory of joint actions is *** method can realize the adaptability of the hydraulic robot knee joint in different movements,and take the flexible action as the optimization goal under the condition of ensuring the movement performance,so as to reduce the damage to the knee joint caused by the foot impact in *** simulation model was built by Adams and Matlab to complete the performance analysis and motion optimization experiment of the knee *** simulation results show that the foot impact force of the experimental model decreases gradually through ***,the method is applied to the hydraulic joint experimental prototype to prove its load capacity and flexible motion control performance.

关键词： Bionic robot Ball double-screw hydraulic joint Robot knee joint Performance analysis Humanoid motion control Flexible control

Incremental cost analysis model of distribution network based on economic dispatch of distributed new-energy storage system

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Clean Energy 2024年第2期8卷 89-103页

作者： Zhuan Zhou Jiayu bian Zhiyong Yu State Grid Xinjiang Electric Power Co. ltdXinjiangChina

With the implementation of China’s carbon-peaking and carbon-neutrality strategy,new energy will achieve leapfrog *** to the good economics of distributed new-energy generation,it can not only save users’own investment,but also help to achieve local consumption of new ***,it will also bring about a series of incremental costs to the power *** paper first enumerates the concept,development status and scheduling mode of a distributed new-energy storage *** on the above,it establishes a new-energy power generation model and an energy storage system charging and discharging model,and proposes a global optimization scheduling model for a distributed new-energy storage system,considering the time-of-use electricity price and taking the lowest total operating cost of the distributed new-energy power generation system as the objective ***,it proposes a distribution network incremental cost analysis model based on the penetration of distributed new *** calculation results show that the incremental cost of grid-connected distributed new energy is 1.0849,1.2585 and 1.3473 yuan/kWh,respectively,which indicates that the global dispatching model can optimize the power consumption structure of a distributed power generation system,and has the function of peak shaving and valley filling,but the incremental cost of the distribution network will also increase.

关键词： distributed new energy electrochemical energy storage economic dispatch distribution network cost time-sharing price

Operation Strategy and Matching of Supply and Demand of CCHP System with Various Building Types

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Journal of Thermal Science 2024年第6期33卷 2203-2220页

作者： LI Yaohong WANG Pengxiang PENG Bin bian Xiaoyang School of Mechanical and Electrical Engineering Lanzhou University of TechnologyLanzhou 730050China

The important indications for assessing CCHP(combined cooling,heating and power)systems are their supply-demand matching characteristics between the user demand side and the energy supply *** characteristics are primarily influenced by different building types and operating *** view of the energy redundancy of the following electric load(FEL)and following thermal load(FTL)operation strategies and the energy deficiency of the following hybrid electric-heating load(FHL)operation strategy,this paper proposes an improved following balanced heat-electrical load(IFBL)operation strategy based on the following balanced heat-electrical load(FBL)operation *** on the energy utilization rate as the objective function,this paper optimizes the installed capacity of CCHP systems in different buildings and proposes an energy factor for evaluating the supply-demand matching characteristics of the *** results show that the energy utilization rate and energy factor of the system under IFBL are optimal relative to the other operation ***,the hotel building has the highest energy utilization rate and the lowest energy factor;on the contrary,the office building has the lowest energy utilization rate and the highest energy ***,the analysis of supply-demand matching for different building types under multiple operating strategies shows that the hospital and hotel systems exhibit optimal supply-demand matching performance under the IFBL strategy,with values of 0.945 and 0.938,respectively;on the contrary,the office system has an optimal supply-demand matching of 0.935 under the FEL *** the FTL strategy,the systems of all three buildings exhibit poor matching performance.

关键词： combined cooling,heating and power system(CCHP) operation strategy energy utilization energyfactor matching supply and demand

Periodic Solutions of Singular Second Order Equations at Resonance

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Acta Mathematica Sinica,English Series 2015年第10期31卷 1599-1610页

作者： Yin Yin WU Ding bian QIAN School of Mathematical Sciences Soochow University Department of Fondamental Courses Wuxi Institute of Technology

In this paper, we study the existence of positive periodic solutions for singular second order equations x＂＋ n2/4＋h（x） = p（t）, where h has a singularity at the origin and n is a positive integer. We give an explicit condition to ensure the existence of positive periodic solutions when h is an unbounded perturbation at infinity by using qualitative analysis and topological dezree theory.

关键词： Second order equations singularity periodic solutions resonance unbounded perturba-tions

Numerical simulation of high-speed train induced ground vibrations using 2.5D finite element approach

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Science China(Physics,Mechanics & Astronomy) 2008年第6期51卷 632-650页

作者： bian XueCheng CHEN YunMin HU Ting Department of Civil Engineering Zhejiang UniversityHangzhou 310027China

An efficient 2.5D finite element numerical modeling approach was developed to simulate wave motions generated in ground by high-speed train passages. Fourier transform with respect to the coordinate in the track direction was applied to re-ducing the three-dimensional dynamic problem to a plane strain problem which has been solved in a section perpendicular to the track direction. In this study, the track structure and supporting ballast layer were simplified as a composite Euler beam resting on the ground surface, while the ground with complicated geometry and physical properties was modeled by 2.5D quadrilateral elements. Wave dissipation into the far field was dealt with the transmitting boundary constructed with fre-quency-dependent dashpots. Three-dimensional responses of track structure and ground were obtained from the wavenumber expansion in the track direction. The simulated wave motions in ground were interpreted for train moving loads traveling at speeds below or above the critical velocity of a specific track-ground system. It is found that, in the soft ground area, the high-speed train operations can enter the transonic range, which can lead to resonances of the track structure and the sup-porting ground. The strong vibration will endanger the safe operations of high-speed train and accelerate the deterioration of railway structure.

关键词： high-speed train moving load ground vibration 2.5D finite element absorbing boundary