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明渠流动S-K模型参数率定的随机搜索法

水利学报 2007年第11期38卷 1364-1370页

作者：芦妍婷廖华胜 donald w.knight 姚勇四川大学水力学与山区河流开发保护重点实验室四川成都610065 Department of Civil Engineering the University of irminghamEdgbaston 四川省遂宁市水利局四川遂宁629000

S-K模型(Shiono and knight Method)是目前进行单一和复合断面顺直棱柱体明渠水力计算较为精细的模型之一。涉及3个待定参数:摩阻系数f、无量纲涡粘性系数λ和二次流影响因子Γ,这3个参数的待定性使该模型在实际工程应用中受到限制。本... 详细信息

S-K模型(Shiono and knight Method)是目前进行单一和复合断面顺直棱柱体明渠水力计算较为精细的模型之一。涉及3个待定参数:摩阻系数f、无量纲涡粘性系数λ和二次流影响因子Γ,这3个参数的待定性使该模型在实际工程应用中受到限制。本文结合大量的水槽试验流量Q及壁面切应力τb结果,采用随机搜寻法,对S-K模型中的3个重要参数进行了同时满足Q和切应力bτ条件下的优化率定。结果表明,参数f变化规律与Colebrook-white公式基本一致,λ和Γ随渠道宽高比Pb/Pw的变化规律较为明显。

关键词：明渠 S-K模型优化率定

FLOw MECHANISMS ANDSEDIMENT TRANSPORT IN COMPOUND CHANNELS

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International Journal of Sediment Research 1999年第2期14卷 217-236页

作者： donald w. knight (1 School of Civil Engineering. The University of Birmingham, Edgbaston, Birmingham, B 15 2TT. UK)

Recent work on the UK Flood Channel Facility (FCF) is described. An overview of tile various experimental programmes. involving overbank flow studies in straight. skewed and meandering channels. is given. Some key results concerning flow mechanisms. resistance. dispcrsion and sediment transport are reviewed. A summary of different methods for estimating the stage-discharge relationship for overbank flows is included. An extensive bibliography is given for those seeking more detailed information.

关键词： Floods Overbank flow Sediment transport Stage-discharge curves

复式断面滩地部分植被条件下水流横向流速分布(英文)

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复式断面滩地部分植被条件下水流横向流速分布(英文)

Lateral distributions of streamwise velocity in compound channels with partially vegetated floodplains

2009水资源与可持续发展高层论坛

作者： donald w knight School of Civil Engineering The University of BirminghamBirminghamB15 2TTUK

＜正＞Natural rivers are commonly characterized by a main channel for primary flow conveyance and a floodplain,often partially covered with vegetation such as shrubs or trees, to carry extra flow during *** hydraulic resistance due to vegetation on the floodplain typically causes a further reduction of flow velocity and increases the velocity difference

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Science China(Technological Sciences) 2009年第11期52卷 3357-3362页

作者： knight donald w School of Civil Engineering The University of Birmingham Birmingham B15 2TT UK

Natural rivers are commonly characterized by a main channel for primary flow conveyance and a floodplain, often partially covered with vegetation such as shrubs or trees, to carry extra flow during floods. The hydraulic resistance due to vegetation on the floodplain typically causes a further reduction of flow velocity and increases the velocity difference between the main channel and the floodplain. As a consequence a strong lateral shear layer leads to the exchange of mass and momentum between the main channel and floodplain, which in turn affects the overall channel conveyance and certain fluvial processes. The prediction of the lateral velocity distribution is important for many flood alleviation schemes, as well as for studies on sediment transport and dispersion in such channels. The present paper proposes a method for predicting the depth-averaged velocity in compound channels with partially vegetated floodplains, based on an analytical solution to the depth-integrated Reynolds-Averaged Navier-Stokes equation with a term included to account for the effects of vegetation. The vegetation is modelled via an additional term in the momentum equation to account for the additional drag force. The method includes the effects of bed friction, drag force, lateral turbulence and secondary flows, via four coefficients f, CD, λ & Γ respectively. The predicted lateral distributions of depth-averaged velocity agree well with the experimental data. The analytical solutions can also be used to predict the distribution of boundary shear stresses, which adds additional weight to the method proposed.

关键词： vegetation compound channel floodplain velocity

REVIEw OF REGIME THEORY OF ALLUVIAL CHANNELS

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Journal of Hydrodynamics 2002年第3期14卷 1-7页

作者： Cao, Shu-You knight, donald w. Hydraulics Lab. of High Speed Flows Sichuan Univ. Chengdu 610065 China Sch. of Civil Eng. Univ. of Birmingham Birmingham B15 2TT United Kingdom

One of the most important problems in river engineering is to determine a stable cross section geometry and slope for an alluvial channel. This has been the subject of considerable research for about a century and continues to be of great practical interest. Ignoring plan geometry, an alluvial channel can adjust its slope, depth and width, to develop a dynamic stable condition in which it can transport a certain amount of water and sediment. The brief history of regime theory and its new development are reviewed in this paper.

关键词： Channel flow Dynamics Slope protection Stability

Engel Subalgebras of n-Lie Algebras

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Acta Mathematica Sinica,English Series 2008年第1期24卷 159-166页

作者： donald w.BARNES 1 Little wonga Rd

Engel subalgebras of finite-dimensional n-Lie algebras are shown to have similar properties to those of Lie algebras. Using these, it is shown that an n-Lie algebra, all of whose maximal subalgebras are ideals, is nilpotent. A primitive 2-soluble n-Lie algebra is shown to split over its minimal ideal, and all the complements to its minimal ideal are conjugate. A subalgebra is shown to be a Cartan subalgebra if and only if it is minimal Engel, provided that the field has sufficiently many elements. Cartan subalgebras are shown to have a property analogous to intravariance.

关键词： n-Lie algebras soluble nilpotent Engel subalgebras

Friction predication on pin-to-plate interface of PTFE material and steel

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Friction 2019年第3期7卷 268-281页

作者： Zhuming BI donald w.MUELLER Depatment of Civil and Mechnical Engineering Purdue University Fort WayneFort Wayne2101EUSA School of Mechanical and Electrical Engineering GuangDong University of TechnologyGuangzhou510006China

In this paper,the friction behavior at a pin-to-plate interface is *** pin and plate are made of Polytetrafluoroethylene(PTFE) and steel,respectively,and there is a reciprocating motion at the *** mathematical models for the relations of design variables and frictions are investigated,and a general procedure is proposed to solve the developed models and predict the friction forces at the interface subjected to given test *** models have been developed to represent intrigued friction behaviors affected by various factors such as pin geometrics and finishes,lubrication conditions,and reciprocating *** test data from experiments is used to verify the effectiveness of the proposed models.

关键词： pin-to-plate friction wear coefficient of frictions PTFE sealing finite element analysis

State of the art of friction modelling at interfaces subjected to elastohydrodynamic lubrication(EHL)

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Friction 2021年第2期9卷 207-227页

作者： Zhuming BI donald w.MUELLER Chris w.J.ZHANG Civil and Mechanical Engineering Purdue University Fort WayneIN 46805USA Department of Mechanical Engineering University of SaskatchewanSaskatoon SK S7N 5A9Canada

Elastohydrodynamic lubrication(EHL)is a type of fluid-film lubrication where hydrodynamic behaviors at contact surfaces are affected by both elastic deformation of surfaces and lubricant *** of contact interfaces under EHL is challenging due to high nonlinearity,complexity,and the multi-disciplinary *** paper aims to understand the state of the art of computational modelling of EHL by(1)examining the literature on modeling of contact surfaces under boundary and mixed lubricated conditions,(2)emphasizing the methods on the friction prediction occurring to contact surfaces,and(3)exploring the feasibility of using commercially available software tools(especially,Simulia/Abaqus)to predict the friction and wear at contact surfaces of objects with relative reciprocating motions.

关键词： elastohydrodynamic lubrication(EHL) lubricant rheology finite element analysis(FEA) friction prediction Simulia/Abaqus surface roughness coefficient of friction(CoF)

Chronic activation of MUC1-C in wound repair promotes progression to cancer stem cells

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Journal of Cancer Metastasis and Treatment 2022年第1期8卷 488-500页

作者： donald w.Kufe Dana-Farber Cancer Institute Harvard Medical SchoolBostonMA 02115USA

The mucin 1(MUC1)gene emerged in mammals to afford protection of barrier epithelial tissues from the external ***1 encodes a transmembrane C-terminal(MUC1-C)subunit that is activated by loss of homeostasis and induces inflammatory,proliferative,and remodeling pathways associated with wound *** a consequence,chronic activation of MUC1-C promotes lineage plasticity,epigenetic reprogramming,and *** driving cancer progression,MUC1-C is imported into the nucleus,where it induces NF-κB inflammatory signaling and the epithelial-mesenchymal transition(EMT).MUC1-C represses gene expression by activating(i)DNA methyltransferase 1(DNMT1)and DNMT3b,(ii)Polycomb Repressive Complex 1(PRC1)and PRC2,and(iii)the nucleosome remodeling and deacetylase(NuRD)***1/2-mediated gene repression is counteracted by the SwI/SNF chromatin remodeling ***1-C activates the SwI/SNF BAF and PBAF complexes in cancer stem cell(CSC)models with the induction of genome-wide differentially accessible regions and expressed ***1-C regulates chromatin accessibility of enhancer-like signatures in association with the induction of the Yamanaka pluripotency factors and recruitment of JUN and BAF,which promote increases in histone activation marks and opening of *** and other findings described in this review have uncovered a pivotal role for MUC1-C in integrating lineage plasticity and epigenetic reprogramming,which are transient in wound repair and sustained in promoting CSC progression.

关键词： MUC1 MUC1-C wound repair CSC lineage plasticity epigenetic reprogramming chromatin remodeling