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A SIMPLIFIED NUMERICAL MODEL OF 3.D GROUNDwater AND SOLUTE TRANSPORT AT LARGE SCALE AREA

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Journal of Hydrodynamics 2010年第3期22卷 319-328页

作者： LIN Lin YANG Jin-Zhong ZHANG Bin ZHU Yan state key {2. of {3. Resources and hydropower engineering Wuhan University Wuhan 430072China Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 China

A simplified numerical model of groundwater and solute transport is developed. At large scale area there exists a big spatial scale difference between horizontal and vertical length scales. In the resultant model, the seepage region is particularly divided into several virtual layers along the z direction and vertical 1-D columns covering x-y 2.D area according to stratum properties. The numerical algorithm is replacing the full 3.D water and mass balance analysis as the 2.D Galerkin finite element method in x- and y-directions and 1-D finite differential approach in the z direction. The reasonable method of giving minimum thickness is successfully used to handle transient change of water table, drying cells and problem of rewetting. The solution of the simplified model is preconditioned conjugate gradient and ORTHOMIN method. The validity of the developed 3.D groundwater model is tested with the typical pumping and backwater scenarios. Results of water balance of the computed example reveal the model computation reliability. Based on a representative 3.D pollution case, the solute transport module is tested against computing results using the MT3.MS. The capability and high efficiency to predict non-stationary situations of free groundwater surface and solute plume in regional scale problem is quantitatively investigated. It is shown that the proposed model is computationally effective.

关键词： groundwater movement solute transport simplified model 3.D mass balance numerical simulation

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 43.072. china 2.key {2. of water Cycle and Related Land Surface Processes, IGSNRR, Chinese Academy of {13., Beijing 100101, {12. 1. state key {2. of {3. Resources and hydropower engineering Science Wuhan University Wuhan 430072 China 2. key laboratory of {2. Cycle and Related Land Surface Processes IGSNRR Chinese Academy of Sciences Beijing 100101 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 resources management, is given in this paper in order to support the implementation of the sustainable water resources management. The suggested integrative frame has been used to study the integrated water resources 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 resources for the local users and the transportation project. Then we formed the developing scenarioes by coupling the available water resources, the recovering rate of water resources 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 resources 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 resources 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

Development of distributed time-variant gain model for nonlinear hydrological systems

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Science china Earth sciences 2005年第6期48卷 713-723页

作者： XIA Jun1, 2. WANG Gangsheng1, TAN Ge1, YE Aizhong2.& G. H. Huang3.1. key {3. of {2. Cycle & Related Land Surface Processes, Institute of Geographic sciences and Natural Resources Research, Chinese Academy of sciences, Beijing 100101, china 2. state key {3. of {2. Resources & {13. engineering sciences, wuhan university, wuhan 43.072. china 3. Faculty of engineering, university of Regina, 3.3. Wascana Parkway, Regina, Sask., S4S 0A2. Canada Correspondence should be addressed to Xia Jun 1. key laboratory of {2. Cycle & Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China 2. state key {2. of water Resources & hydropower engineering sciences Wuhan University 430072 Wuhan China 3. Faculty of engineering University of Regina 3737 Wascana Parkway S4S 0A2 Sask Regina Canada

In this paper, a rainfall-runoff modeling system is developed based on a nonlinear Volterra functional series and a hydrological conceptual modeling approach. Two models, i.e. the time-variant gain model (TVGM) and the distributed time-variant gain model (DTVGM) that are built on the platform of Digital Elevation Model (DEM), Remote Sensing (RS) and Unit Hydro-logical Process were proposed. The developed DTVGM model was applied to two cases in the Heihe River Basin that is located in the arid and semiarid region of northwestern china and the Chaobai River basin located in the semihumid region of northern china. The results indicate that, in addition to the classic dynamic differential approach to describe nonlinear processes in hy-drological systems, it is possible to study such complex processes through the proposed sys-tematic approach to identify prominent hydrological relations. The DTVGM, coupling the advan-tages of both nonlinear and distributed hydrological models, can simulate variant hydrological processes under different environment conditions. Satisfactory results were obtained in fore-casting the time-space variations of hydrological processes and the relationships between land use/cover change and surface runoff variation.

关键词： hydrological process, nonlinearity, time-variant gain model, distributed hydrological model.

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 {3. 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

Effect of Limestone Powder on Microstructure of Concrete

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Journal of wuhan university of Technology(Materials Science) 2010年第2期25卷 328-331页

作者：刘数华 state key {2. of {3. Resource and hydropower engineering Science Wuhan University

The effect of limestone powder on microstructure of concrete was studied by using mercury intrusion porosimetry （MIP）, backscattering scanning electron（BSE）, scanning electron mi- croscopy （SEM） and X-ray diffraction （XRD） techniques. The experimental results show that the compressive strength of concrete containing 100 kg/m3.limestone powder can meet the strength requirement. Limestone powder has not pozzolanic activity; it is still unhydrated at the age of 2. days. But its filling effect can make the paste matrix and the interfacial transition zone between matrix and aggregate denser, which will improve the performance of concrete.

关键词： concrete limestone powder microstructure filling effect hydration characteristic

SIMULATION OF SEDIMENT DEPOSITION IN A CAVITY WITH FREE SURFACE

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Journal of Hydrodynamics 2010年第5期22卷 626-633页

作者： ZHANG Xiao-feng CUI Zhan-feng LU Xin-hua state key {2. of {3. Resource and hydropower engineering Science Wuhan University Wuhan 430072 China Yangtze River Scientific Research Institute Wuhan 430010 China

Studies of the flow and sediment movement in a cavity with free surface were mostly limited to physical modeling experiments. In this study, the sediment movement is characterized in detail using a 3.D turbulent numerical model. To close the Reynolds equations, the standard k-ε model is employed. The VOF method is adopted to capture the time varying free surface and the porosity method is introduced to deal with the irregular boundary and the varying bed deformation. The computation results agree well with the experimental data in major aspects such as the vertical distribution of the sediment concentration and the deposition topography in the cavity. The comparisons show that this model can well predict the flow structure and the sediment movement and also the river bed deformation in a cavity.

关键词： 3.D turbulent flow cavity flow free surface VOF porosity sediment transport

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 {3. 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

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 {3. 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

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 {3. 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 3.% 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 {3. 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