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Friction 2020年第1期8卷 182-197页

作者： Zhiqiang TU Enzhu HU Bangbang WANG Karl D DAVID Philipp SEEGER Martin MONEKE Ralph STENGLER Kunhong HU Xianguo HU Department of Chemical and Materials Engineering Hefei UniversityHefei 230601China School of Mechanical Engineering Institute of TribologyHefei University of TechnologyHefei 230009China Department of Mechanical Engineering School of EngineeringUniversity of BirminghamBirmingham B152TTUnited Kingdom Darmstadt Institute of Plastics Engineering University of Applied Sciences DarmstadtDarmstadt 64295Germany

A novel green lubricating oil additive(carbon quantum dot(CQD)particle‐doped nickel(Ni‐CQD))was synthesized from citric acid and nickel *** effects of CQD and Ni‐CQD nanoparticles on the tribological behaviors of polyethylene glycol(PEG200)were investigated under different loads and reciprocation *** results indicate that CQD and Ni‐CQD particles can both enhance the lubrication properties of ***,the Ni‐CQD nanoparticles enhanced the lubrication properties more than the plain CQD particles *** average friction coefficient and wear rate of PEG200 containing 2 wt%Ni‐CQDs were reduced by 35.5%and 36.4%,respectively,compared to PEG200 containing pure CQDs under a load of 8 N and reciprocation speed of 25 mm/s over 60 *** friction and wear mechanisms are attributed to the fact that friction induces the Ni‐CQDs to participate in the formation of a tribofilm,resulting in a low friction coefficient and wear rate.

关键词： friction dynamics joint clearance numerical models impact durability

numerical MODEL FOR FLOW THROUGH SUBMERGED VEGETATION REGIONS IN A SHALLOW LAKE

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Journal of Hydrodynamics 2011年第2期23卷 170-178页

作者： WANG Pei-fang WANG Chao Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes Ministry ot Education College of Environment Hohai University Nanjing 210098 China

Aquatic vegetation has a significant impact on water currents. To evaluate the effects of changes in the aquatic vegetation on water currents of different velocity, a 3-D hydrodynamic model was then developed by taking into consideration of the additional hydraulic resistance of the aquatic plants. The Navier- Stokes equations were then solved using the SIMPLE method and the k - e＂ turbulence model. Calculations using the established models were used to forecast the vertical distribution of the horizontal velocity and horizontal flow under the transmission conditions of the South-North Water Diversion in the Nansi Lake. And comparative calculation for the flow velocity was also performed using the simplified method of assigning a high roughness coefficient to the lake bed in the same area. Results suggest that adding additional hydraulic resistance of the aquatic plants is feasible. The calculation errors between simulation result and the field observed data are smaller than 15%, while, those errors are up to 35% if the influence of aquatic vegetation is dealt with the simplified method.

关键词： lakes numerical models hydraulic resistance aquatic vegetation

Quantitative investigation on collapse margin of steel high-rise buildings subjected to extremely severe earthquakes

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Earthquake Engineering and Engineering Vibration 2018年第3期17卷 445-457页

作者： Lin Xuchuan Mikiko Kato Zhang Lingxin Masayoshi Nakashima Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering MechanicsChina Earthquake AdministrationHarbinChina Nikken Sekkei LTD. OsakaJapan Kyoto University KyotoJapan Kobori Research Complex TokyoJapan

Reponses of structures subjected to severe earthquakes sometimes significantly surpass what was considered in the *** is important to investigate the failure mechanism and collapse margin of structures beyond design,especially for high-rise *** this study,steel high-rise buildings using either square concrete-filled-tube（CFT） columns or steel tube columns are designed.A detailed three-dimensional（3 D） structural model is developed to analyze the seismic behavior of a steel high-rise towards a complete *** effectiveness is verified by both component tests and a full-scale shaking table *** collapse margin,which is defined as the ratio of PGA between the collapse level to the design major earthquake level（Level 2）,is quantified by a series of numerical simulations using incremental dynamic analyses（IDA）.The baseline building using CFT columns collapsed with a weak first story mechanism and presented a collapse margin ranging from 10 to *** significant variation in the collapse margin was caused by the different characteristics of the input ground *** building using equivalent steel columns collapsed earlier due to the significant shortening of the locally buckled columns,exhibiting only 57% of the collapse margin of the baseline *** influence of reducing the height of the first story was quite *** shortened first story not only enlarged the collapse margin by 20%,but also changed the collapse mode.

关键词： collapse quantification steel high-rise building numerical models local buckling collapse mechanism

numerical modeling of external light gauge steel framed wall systems exposed to bushfire flame zone conditions

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Frontiers of Structural and Civil Engineering 2024年第9期18卷 1424-1444页

作者： Sahani HENDAWITHARANA Anthony ARIYANAYAGAM Mahen MAHENDRAN Faculty of Engineering Queensland University of TechnologyBrisbaneQLD 4000Australia

Bushfire-related building losses cause adverse economic impacts to countries prone to *** materials and components play a vital role in reducing these ***,due to high costs of experimental studies and lack of numerical studies,the heat transfer behavior of building’s external components in bushfire-prone areas has not been adequately *** large-scale heat transfer models are developed using Computational Fluid Dynamics(CFD)tools,and the availability of CFD models for heat transfer in building components improves the understanding of the behavior of systems and systems of ***,this paper uses a numerical modeling approach to investigate the bushfire/wildfire resistance of external Light gauge Steel Framed(LSF)wall *** full-scale and small-scale heat transfer models were developed for the LSF wall *** results of six internal and external LSF wall systems with varying plasterboard thickness and cladding material were used to validate the developed *** study was then extended to investigate the bushfire resistance of seven external wall systems under two different bushfire flame zone *** results illustrate the significant effects of fire curves,LSF wall components and configuration on the heat transfer across the *** have shown 1)the favorable performance of steel cladding and Autoclaved Aerated Concrete(AAC)panels when used on the external side of wall systems and 2)the adequacy of thin-walled steel studs’load-bearing capacity during bushfire *** study has shown that most of the investigated external LSF walls could be reused with cost-effective retrofitting such as replacing the Fire Side(FS)steel cladding after bushfire ***,this study has advanced the understanding of the behavior of external light steel framed walls under bushfire flame zone conditions.

关键词： bushfires flame zone external light gauge steel framed walls heat transfer analyses numerical models

numerical Modelling of Velocity and Temperature Distributions of the Buoyancy Convection Effect in KNbO3 Melt

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Chinese Physics Letters 2002年第7期19卷 1007-1009页

作者：刘照华金蔚青等 ShanghaiInstituteofCeramics ChineseAcademyofSciencesShanghai200050

numerical modelling of velocity and temperature fields in high-temperature KNbO3 melt of a loop-shaped Pt wire heater is carried out by using the commercial computational code ANSYS for the mathematical solution of the governing equations. Based on the experimental boundary conditions and the Boussinesq approximation, the numerical modelling of a steady and two-dimensional model is applied to study the process under consideration of the buoyancy-driven convection condition. The result is compared with the previous experimental and theoretical data obtained in our laboratory, and the former is in agreement with the latter. Thus a theoretical guide for reasonable growth conditions is provided by studying in depth the real fluid flow effects in the crystal growth from the melt.

关键词： numerical models

A review of friction models in interacting joints for durability design

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Friction 2017年第1期5卷 1-22页

作者： Zulfiqar A.KHAN Vivek CHACKO Hammad NAZIR NanoCorr Energy & Modelling(NCEM)Research Department of Design & Engineering Bournemouth University Bournemouth United Kingdom

This paper presents a comprehensive review of friction modelling to provide an understanding of design for durability within interacting *** is a complex phenomenon and occurs at the interface of two components in relative *** the last several decades,the effects of friction and its modelling techniques have been of significant interests in terms of industrial *** is however a need to develop a unified mathematical model for friction to inform design for durability within the context of varying operational *** dynamic mechanisms model for the design of control systems has not incorporated friction phenomena due to non-linearity ***,the tribological performance concurrently with the joint dynamics of a manipulator joint applied in hazardous environments needs to be fully *** the dynamics and impact models used in mechanical joints with clearance have also been *** inclusion of reliability and durability during the design phase is very important for manipulators which are deployed in harsh environmental and operational *** revolute joint is susceptible to failures such as in heavy manipulators these revolute joints can be represented by lubricated conformal sliding *** presence of pollutants such as debris and corrosive constituents has the potential to alter the contacting surfaces,would in turn affect the performance of revolute joints,and puts both reliability and durability of the systems at greater risks of *** literature is identified and a review on the latest developments of the science of friction modelling is presented *** review is based on a large volume of *** in the relevant field have been identified to capitalise on for future ***,this review will bring significant benefits to researchers,academics and industry professionals.

关键词： friction dynamics joint clearance numerical models impact durability

On the Importance of High-Resolution in Large-Scale Ocean models

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Advances in Atmospheric Sciences 2021年第10期38卷 1621-1634页

作者： Eric *** Xiaobiao XU Center for Ocean-Atmospheric Prediction Studies(COAPS) Florida State UniversityTallahasseeFL32310USA

Eddying global ocean models are now routinely used for ocean prediction,and the value-added of a better representation of the observed ocean variability and western boundary currents at that resolution is currently being evaluated in climate *** overview article begins with a brief summary of the impact on ocean model biases of resolving eddies in several global ocean-sea ice numerical ***,a series of North and Equatorial Atlantic configurations are used to show that an increase of the horizontal resolution from eddy-resolving to submesoscale-enabled together with the inclusion of high-resolution bathymetry and tides significantly improve the models’abilities to represent the observed ocean variability and western boundary ***,the computational cost of these simulations is extremely large,and for these simulations to become routine,close collaborations with computer scientists are essential to ensure that numerical codes can take full advantage of the latest computing architecture.

关键词： ocean modeling numerical models horizontal resolution boundary currents

Evaluating Parameterizations for Turbulent Fluxes over the Landfast Sea-Ice Surface in Prydz Bay, Antarctica

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Advances in Atmospheric Sciences 2023年第10期40卷 1816-1832页

作者： Fangyuan CHENG Qinghua YANG Changwei LIU Bo HAN Shijie PENG Guanghua HAO School of Atmospheric Sciences Sun Yat-sen Universityand Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519080China National Marine Environmental Forecasting Center Beijing 100081China

It is crucial to appropriately determine turbulent fluxes in numerical *** data collected in East Antarctica from 8 April to 26 November 2016,this study evaluates parameterization schemes for turbulent fluxes over the landfast seaice surface in five numerical *** Community Noah Land Surface Model with Multi-Parameterizations Options(Noah_mp)best replicates the turbulent momentum flux,while the Beijing Climate System Model(BCC_CSM)produces the optimum sensible and latent heat *** particular,two critical issues of parameterization schemes,stability functions and roughness lengths,are *** tests indicate that roughness lengths play a decisive role in model *** on the observed turbulent fluxes,roughness lengths over the landfast sea-ice surface are *** results,which can provide a basis for setting up model parameters,reveal that the dynamic roughness length(z0m)increases with the increase of frictional velocity(u*)when u*≤0.4 m s^(−1) and fluctuates around 10^(−3 )m when u*>0.4 m s^(−1);thermal roughness length(z0t)is linearly related to the temperature gradient between air and sea-ice surface(ΔT)with a relation of lg(z0t)=−0.29ΔT−3.86;and the mean water vapor roughness length(z0q)in the specific humidity gradient(Δq)range ofΔq≤−0.6 g kg^(−1) is 10^(−6) m,3.5 times smaller than that in the range ofΔq˃−0.6 g kg^(−1).

关键词： turbulent fluxes Antarctica landfast sea-ice surface parameterization evaluating numerical models

Adhesion and surface forces in polymer tribology——A review

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Friction 2018年第2期6卷 143-155页

作者： Nikolai MYSHKIN Alexander KOVALEV Metal-Polymer Research Institute of Belarus National Academy of Sciences State Key Laboratory of Tribology Tsinghua University

Polymer tribology is a fast growing area owing to increasing applications of polymers and polymer composites in industry, transportation, and many other areas of economy. Surface forces are very important for polymer contact, but the real origin of such forces has not been fully investigated. Strong adhesive interaction between polymers leads to an increase in the friction force, and hence, the asperities of the material may be removed to form wear particles or transfer layers on the counterface. The theory of polymer adhesion has not been completely elucidated yet and several models of adhesion have been proposed from the physical or chemical standpoints. This paper is focused on the research efforts on polymer adhesion with emphasis on adhesion mechanisms, which are very important in the analysis of polymer friction and wear.

关键词： friction dynamics joint clearance numerical models impact durability

numerical study of the tides and residual currents in the Qiongzhou Strait

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Chinese Journal of Oceanology and Limnology 2009年第4期27卷 931-942页

作者：陈长霖李培良侍茂崇左军成陈美香孙海萍 Physical Oceanography Laboratory Ministry of EducationOcean University of China Key Laboratory of Coastal Disaster and Defense Hohai University CNOOC New Energy Investment Co.Ltd.

Based on the three-dimensional ECOM model,the tide,tide-induced residual current,wind-driven and density currents in the Beibu (Tonkin) Gulf and Qiongzhou Strait are diagnostically computed in fine *** tides and tidal currents in the Beibu Gulf and Qiongzhou Strait are well *** model results show that the semidiurnal tidal wave propagates eastward from the Beibu Gulf through Qiongzhou Strait,while diurnal tidal waves enter the strait from both the eastern and western sides and interact on the southeast coast of the *** formation processes of the residual currents in Qiongzhou Strait in summer (August) and winter (January) are mainly *** is shown that the total residual currents (coupling effect of wind,tide and density) in the strait are westward in both summer and *** water volume transported from the east to west into the Beibu Gulf is 0.026 Sv in summer and 0.116 Sv in *** experiments indicate that the dominant factor affecting the residual currents in the strait is not the wind stress but the tidal *** westward tide-induced residual current,driven by the tidal rectification,is rather strong in the strait with water volume transport of 0.063 *** wind in summer only reduces the westward tide-induced residual current to a certain extent,and the wind in winter approximately doubles the westward tide-induced residual current through the *** density current contributes little to the total residual current in both summer and winter.

关键词： numerical models tides residual currents wind-driven currents South China Sea QiongzhouStrait