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Differential Hydrological Grey Model (DHGM) with self-memory function and its application to flood forecasting

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Science china(Technological sciences) 2009年第4期52卷 1039-1049页

作者： CHEN XiangDong1, XIA Jun1,2.& XU Qian3 1 key laboratory of {2. Cycle and Related Land Surface Processes, Institute of Geographic sciences and Natural resources Research, Chinese Academy of sciences, Beijing 100101, china 2.state key laboratory of {2. resources and {12. engineering Science, wuhan university, wuhan 430072. china 3 School of Hydrology and {2. resources, Hohai university, Nanjing 2.0098, china key laboratory of {2. Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China state key {2. of water resources and hydropower engineering Science Wuhan University Wuhan China School of Hydrology and water resources Hohai University Nanjing China

This paper addresses a problem of flood forecasting with the self-memory function. Considering flood forecasting’s uncertainty and updating demand, a hybrid hydrological model, namely Differential Hy- drological Grey Model with self-memory function (DHGM-SM), is developed. The model has two fold features. One is to establish a self-memorization equation linked with DHGM, that could extract useful information from past data series and realize updating of hydrological dynamic process. The other is that this model has higher efficiency relative to original hydrological model without self-memory func- tion. This approach was applied to river flow forecasting of two representative basins in Tunxi of South china and Daqinggou of North china. It is shown that this hybrid method has satisfactory forecasting accuracy by examination of both calibration and validation.

关键词： differential grey model the self-memorization principle real-time forecasting faded-memory recursive least square method

QUALIFICATION OF UNCERTAINTY FOR SIMULATING SOLUTE TRANSPORT IN THE HETEROGENEOUS MEDIA WITH SPARSE GRID COLLOCATION METHOD

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Journal of Hydrodynamics 2009年第6期21卷 779-789页

作者： SHI Liang-sheng YANG Jin-zhong state key {2. of water resources and hydropower engineering Science Wuhan University Wuhan 430072 China The Sonny Astani Department of Civil and Environmental engineering University of Southern California Los Angeles CA 90089 USA

The sparse grid collocation method is discussed to qualify the uncertainty of solute transport. The Karhunen-Loeve （KL） expansion is employed to decompose the log transformed hydraulic conductivity. The head, velocity and concentration fields are represented by the Lagrange polynomial expansion. A sparse grid collocation method is then used to reduce the original stochastic partial differential equations to a set of deterministic equations which is collocated at selected interpolation （collocation） points. The collocation points are constructed by the Smolyak algorithm. The accuracy, efficiency and convergence property of sparse grid collocation method are investigated by numerical experiments. The analysis shows that stochastic collocation strategy helps to decouple stochastic computations, and all the numerical computation is possible to be implemented by existing deterministic finite element codes. The proposed method provides an efficient way to evaluate the uncertainty of the solute transport in the heterogeneous media.

关键词： stochastic partial differential equations collocation method solute transport uncertainty

Coupling the hydrological and ecological process to implement the sustainable water resources management in Hanjiang River Basin

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Science china(Technological sciences) 2009年第11期52卷 3240-3248页

作者： ZHANG Xiang1 & XIA Jun2.1 state key {2. of water resources and hydropower engineering Science, wuhan university, wuhan 430072. china 2.key {2. of water Cycle and Related Land Surface Processes, IGSNRR, Chinese Academy of {12., Beijing 100101, china state key {2. of water resources and hydropower engineering Science Wuhan University Wuhan China key laboratory of {2. Cycle and Related Land Surface Processes IGSNRR Chinese Academy of Sciences Beijing China

Research on the combination of hydrological variation and ecological demands plays an important role in water availability assessment and sustainable management on basin scale. An integrative frame, consisting of hydrological regime modelling, ecological water demands estimation and renewable {2. management, is given in this paper in order to support the implementation of the sustainable water {2. management. The suggested integrative frame has been used to study the integrated water {2. management in southern Hanjiang River Basin which is the water source of South-toNorth water Transportation Project in china. SWAT (soil and water assessment tool) model was used to simulate the monthly averaging streamflow and the amounts of ecological water demands in stream were also estimated in order to evaluate the available water {2. for the local users and the transportation project. Then we formed the developing scenarioes by coupling the available water {2., the recovering rate of water {2. in natural water cycle, the local water use rate and the amounts of the water transported to North, and used the Scheafer model to analyze their evolving trajectories. Eventually, the sustainable water {2. management measures were assembled by the comprehensive evaluation of the scenarioes. The research indicates that the integrative frame provided a new way for the integrated water {2. management in river basin.

关键词： SWAT (soil and water assessment tool) Scheafer model ecological water demands water resources availability sustainable water resources management

MODELING UNCONFINED SEEPAGE FLOW USING THREE-DIMENSIONAL NUMERICAL MANIFOLD METHOD

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Journal of Hydrodynamics 2010年第4期22卷 554-561页

作者： JIANG Qing-hui DENG Shu-shen ZHOU Chuang-bing LU Wen-bo School of Civil engineering Wuhan University Wuhan 430072 China state key {2. of water resources and hydropower engineering Science Wuhan University Wuhan 430072 China

Three-dimensional numerical manifold method for unconfined seepage analysis is proposed in this *** constructing hydraulic potential functions of the manifold element,the element conductivity matrix and the global simultaneous equations for unconfined seepage analysis are derived in *** algorithm of locating the free surface and the formula for seepage forces are also ***-dimensional manifold method employs the tetrahedral mathematical meshes to cover the whole material *** the iterative process for locating the free surface,the manifold method can achieve an accurate seepage analysis of the saturated domain below the free surface with mathematical meshes *** the shape of manifold elements can be arbitrary,the disadvantage of changing the permeability of transitional elements cut by the free surface in the conventional Finite Element Method（FEM） is removed,and the accuracy of locating the free surface can be ***,the seepage force acting on the transitional elements can be accurately calculated by the simplex *** results for a typical example demonstrate the validity of the proposed method.

关键词： three-dimensional seepage numerical manifold method free surface mathematical mesh manifold element

Characterization of Pozzolanic Reaction and Its Effect on the C-S-H Gel in Fly Ash-cement Paste

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Journal of wuhan university of Technology(Materials Science) 2011年第2期26卷 320-325页

作者：王磊何真 state key {2. of water resources and hydropower engineering Science Wuhan University

High resolution solid-state 2.Si MAS NMR,combined with XRD,SEM and FTIR were used to characterize the pozzolanic activity of FA,type of main pozzolanic reaction products,and the effect of pozzolanic reaction on the C-S-H microstructure in fly ash-cement （FC） *** experimental results indicate that in the hydrated FC paste with 30% dosage of FA at 3 d,FA partially participated in the pozzolanic reaction,while,at 12. d,FA largely *** the hydration of FC paste at laboratory temperature,the pozzolanic reaction products are C-S-H gel rather than zeolitic ***,after the covalent bonds of Si-O-Si,Si-O-Al and Al-O-Al in the structure of FA are broken,monosilicates Si-OH and Al-OH groups form,these chemical species can connect C-S-H dimers,thus producing more Al-free C-S-H and aluminous C-S-H than in the plain cement *** increased content of Al for Si substitution in the bridging tetrahedra of C-S-H may decrease the stability of C-S-H,which results in a rather obvious loss in the mechanical strength of hardened FC paste.

关键词： NMR C-S-H microstructure dimer polymerization

EXPERIMENTAL STUDY OF LANDSLIDE DAM-BREAK FLOOD OVER ERODIBLE BED IN OPEN CHANNELS

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Journal of Hydrodynamics 2009年第1期21卷 124-130页

作者： YAN Jun CAO Zhi-xian LIU Huai-han CHEN Li state key {2. of water resources and hydropower engineering Science Wuhan University Wuhan 430072China Changjiang waterway Institute of Planning Design and Research Wuhan 430011 China

Large-scale landslide dams may block the river flow and cause inundation upstream, and subsequently fail and result in severe flooding and damage in the downstream. The need for enhanced understanding of the inundation and flooding is evident. This article presents an experimental study of the inundation and landslide dam-break flooding over erodible bed in open channels. A set of automatic water-level probes is deployed to record the highly transient stage, and the post-flooding channel bed elevation is measured. New experimental data resources are provided for understanding the processes of landslide-induced flooding and for testing mathematical rivers models.

关键词： landslide dam dam-break sediment transport

A hybrid matching method for geospatial services in a composition-oriented environment

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Science china(Technological sciences) 2010年第S1期53卷 213-220页

作者： LUO An 1,2.WANG YanDong 1,2.& CHEN ShengHua 2.1 state key {2. of Software engineering,wuhan university,wuhan 430072.china 2.state key {2. of Information engineering in Surveying,Mapping and Remote Sensing,wuhan university,wuhan 430079,china state key {2. of Software engineering Wuhan University Wuhan China state key {2. of Information engineering in Surveying Mapping and Remote Sensing Wuhan University Wuhan China

With the development of Internet and GIS,large volumes of spatial data,powerful computing resources and many spatial data processing functions are published in the form of Web *** suitable geospatial services in the composition-oriented environment is a crucial *** semantic Web provides a kind of technology to find and compose various service resources automatically through the *** paper proposes a hybrid method for the semantic matching of geospatial *** method includes two *** 1 puts forward a multi-level semantic matching approach,which matches single geospatial service at four levels:classification,input/output,precondition/effect and the quality of service(QoS).This multi-level matching approach makes single service matching quicker and more *** 2.puts forward a matching algorithm for a geospatial service chain based on the *** algorithm adopts a trace algorithm,taking account of the effect of the *** restricts the input/output parameters of the current service by the input/output parameters of service chain,pre-service and *** matches the atomic service dynamically in a composition-oriented environment,and accurately converts the abstract model of geospatial services into an executable geospatial service chain.A case study of the flood analysis for the Poyang Lake illustrates the effectiveness of our context-based matching method for geospatial services.

关键词： geospatial services semantic context composition service match

Non-Uniform Sediment Transport Downstream from Reservoir

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Transactions of Tianjin university 2008年第4期14卷 263-270页

作者：李义天陈飞 state key {2. of water resources and hydropower engineering sciences Wuhan University

The transport characters of non-uniform sediment before and after the reservoir operation are compared and analyzed. Field data from the Three Gorges Reservoir (TGR), Danjiangkou, and Sanmenxia reservoir indicate that the transport character of coarse particle is various in different reaches. Before the reservoir operation, the dramatic decrease of the hydraulic condition in some reaches is the main reason to cause the coarse particle deposited. After the reservoir operation, almost all grain sized sediment may be eroded, when the reach is eroded seriously. However, the transport character of the coarse particle will be consistent with what it was before, when the reach is not eroded seriously. The deposition amount will be less than its pre-dam value, and it will tend to decrease with the time going on. Erosion of fine particle results from its unsaturation. Longdistance erosion downstream from reservoir is caused by shortage of the supply from riverbed, especially the shortage of fine particle.

关键词： downstream from reservoir grain sized sediment hydraulic condition

THEORETICAL ANALYSIS AND NUMERICAL SIMULATION OF TURBULENT FLOW AROUND SAND WAVES AND SAND BARS

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Journal of Hydrodynamics 2009年第2期21卷 292-298页

作者： LIU Shi-he XIONG Xiao-yuan LUO Qiu-shi state key {2. of water Resource and hydropower engineering Science Wuhan University Wuhan 430072 China School of water Resource and hydropower Wuhan University Wuhan 430072 China Changjiang River Administration of Navigation Affairs MC Wuhan 430014 China

Natural rivers usually possess sand waves and sand bars. In this article, the rapid distortion theory was used to study the turbulent flow over sand waves. The results show that the pre-existing sheafing motion and upstream anisotropy of the turbulence flow would have significant effect on the turbulent structures, and hence the memory effect should be taken into consideration. Furthermore, the 2.D mathematical model was employed to simulate the unsteady flow around the Taiping Sand Bar in the lower reach of the Yangtze River and the time step effect on the unsteady flow simulation with the implicit scheme was discussed at the same time. The results show that the implicit scheme keeps effective until the time step reaches a certain number, and the calculated water levels and velocities are in agreement with the observed data.

关键词： sand wave sand-bar rapid distortion theory numerical simulation