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C-S-H Cluster Microstructure and Bonding Force Investigation base on AFM Technology

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Journal of wuhan university of Technology(Materials science) 2010年第4期25卷 592-595页

作者：张博何真 state key laboratory of water resources and hydropower engineering science Wuhan University

AFM （atomic force microscopy） technology was applied on C-S-H （calcium silicate hydrate phase） microstructure investigation. The topographies of hydrated C3S （Tricalcium silicate） samples were firstly acquired with AFM. Accordingly, C-S-H can be identified according its pattern. Then the hydrated pssortland cement samples at different curing time were scanned with AFM. The topographies and force displacement curve were acquired and its characters at different days were summarized and analyzed. These results are very meaningful for C-S-H microstructure further investigation and cement-base material macro scale properties improvement.

关键词： C-S-H atomic force microscopy microstructure tricalcium silicate

Experimental Study on the Distribution of Soil Nitrate and Ammonium Nitrogen under Controlled Drainage

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wuhan university Journal of Natural sciences 2009年第6期14卷 532-536页

作者： YANG Lin, HUANG Jiesheng, ZHAO Lirong, HUANG Zhiqiang state key laboratory of water resources and hydropower engineering science, wuhan university, wuhan 430072, Hubei, china state key laboratory of water resources and hydropower engineering science Wuhan University Wuhan China

A field experimental project was set up to assess the effects of controlled drainage on the distribution and concentration of nitrogen in the soil at the Irrigation and Drainage Experimental Station under Four-Lake engineering Administration of Jingzhou City, Hubei Province. Two plots drain runoff by controlled drainage system, with an area of 0.1 hm^2 （20 m×50 m） each. The third one with an area of 0.04 hm^2 （8 m×50 m） has a conventional subsurface drainage system. Under this experimental condition, the study draws the following conclusions： ① The controlled drainage system has a remarkable effect on the diminishing ratios of nitrate nitrogen between neighboring layers. It is presented that the diminishing ratio increases with the raising height of drain outlet. Controlled drainage system also reduces the transference of nitrate nitrogen in topsoil.② Different from nitrate nitrogen, the concentration of ammonium nitrogen is stable along the longitudinal section of soil, which is little affected by the controlled drainage system. It indicates that the concentration of ammonium nitrogen decreases according to the lowering of controlling height of the drain outlet.

关键词： controlled drainage nitrate nitrogen ammonium nitrogen controlling height of drain outlet

SIMULATIONS OF THE THREE-DIMENSIONAL TOTAL DISSOLVED GAS SATURATION DOWNSTREAM OF SPILLWAYS UNDER UNSTEADY CONDITIONS

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Journal of Hydrodynamics 2010年第4期22卷 598-604页

作者： FU Xiao-li LI Dan ZHANG Xiao-feng state key laboratory of water resources and hydropower engineering science Wuhan University Wuhan 430072 China

Dams are often operated in a way to discharge over the spillways,which would cause a high dissolved concentration of air and be harmful to *** bubble transfer and the water surface transfer play an important role in affecting the concentration of the Total Dissolved Gas（TDG）.Based on recent numerical simulations of the total dissolved gas saturation,in this article,a two-phase TDG transport equation is adopted to develop an unsteady three-dimensional（3-D） two-phase flow Computational Fluid Dynamics（CFD） model,including a number of parameters such as water depth,pressure and air volume *** model is used to predict the hydrodynamics and the TDG distribution under unsteady discharge *** agreement between measured and numerical results is obtained for a case study.

关键词： gas supersaturation anisotropic two-phase flow

UNIFIED MODEL FOR SPLASH DROPLETS AND SUSPENDED MIST OF ATOMIZED FLOW

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Journal of Hydrodynamics 2008年第1期20卷 125-130页

作者： LIU Shi-he SUN Xiao-fei LUO Jing state key laboratory of water resources and hydropower engineering science Wuhan University Wuhan 430072 China

In this article, the unified mathematical model for splash droplets and suspended mist of atomized flow was established, which classifies the atomized sources into the splash source and the suspended source. For the splash source, the Lagrangian method was used to simulate the random motion of splash water droplets, and for the suspended source the theory of air-water two-phase flow was used to simulate the mist flow moving in particle clouds. The rainfall intensity of the atomized flow was obtained by summarizing the rainfall intensities relative to the above two types of atomized sources. Both experimental data and prototype observation data were used for the verification of the mathematical model. For both the distribution of rainfall intensity, and the outer edge of the atomized flow, the simulation results are in agreement with the experimental data or prototype observation data.

关键词： two phase flow atomized flow splash water drop suspended mist

A 2-D HYDRODYNAMIC MODEL FOR THE RIVER,LAKE AND NETWORK SYSTEM IN THE JINGJIANG REACH ON THE UNSTRUCTURED QUADRANGLES

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Journal of Hydrodynamics 2010年第3期22卷 419-429页

作者： ZHANG Xi-bing HU De-chao WANG Min state key laboratory of water resources and hydropower engineering science Wuhan University Wuhan430072 China Yangtze River Scientific Research Institute Wuhan 430010 China state key laboratory of Hydroscience and engineering Tsinghua University Beijing 100084 China

The main river, the Dongting Lake and river networks in the Jingjiang reach of the Yangtze River constitute a complex water system, for which a full 2-D hydrodynamic model is established instead of the traditional 1-D or compound models for simulation of such complex systems, based on the latest developments of computer technologies and numerical methods. To better handle irregular boundaries and keep the computation cost well in a reasonable limit, unstructured grids of moderate scale are used. In addition, a dynamic boundary tracking method is proposed to simulate variable flow domains at different floods, especially, when the moderate scale gird can not describe flows in narrow river-network channels at low water levels. The t9 semi-implicit method and the Eulerian-Lagrangian Method （ELM） are adopted, which make the model unconditionally stable with respect to the gravity wave speed and Courant number restrictions. Properties and efficiency of the model are discussed, and it is concluded that the new model is robust and efficient enough for the simulation of a big, complex water system. Validation tests show that the simulation results agree well with field data. It takes about 0.96 h to complete the computation of a 76 d flood, which indicates that the model is efficient enough for engineering applications.

关键词： 2-D numerical model river network unstructured grid semi-implicit Eulerian-Lagrangian Method (ELM) boundarytracking

Experiments on Development of Channel Pattern in the Process of River Reformation

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四川大学学报（工程科学版） 2005年第S1期37卷 128-132页

作者： ZHANG Junyong CHEN Li LIU Yucheng DING Zhiliang(state key Lab.of water resources and hydropower Eng.Sci.,wuhan Univ.,wuhan 430072,china) Lab. of water resources and hydropower Eng. Sci. Wuhan Univ. Wuhan 430072 China

The changing of flow conditions caused by construction of hydro-projects will result in river's refor- mation and development of channel *** this paper,the development of channel pattern in the process of reformation is studied by means of flume *** of slope,grain size,angle-of-inflow,dis- charge and discharge process are comprehensively analyzed according to the experimental *** was found that the channel would be widened as the river slope or discharge increased and grain s...

关键词： reformation process channel pattern angle-of-inflow discharge process

LARGE EDDY SIMULATION OF THE INTERACTION BETWEEN WALL JET AND OFFSET JET

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Journal of Hydrodynamics 2011年第5期23卷 544-553页

作者： LI Zhi-wei HUAI Wen-xin HAN Jie state key laboratory of water resources and hydropower engineering science Wuhan University Wuhan 430072 China

The interaction between a plane wall jet and a parallel offset jet is studied through the Large Eddy Simulation （LES）. In order to compare with the related experimental data, the offset ratio is set to be 1.0 and the Reynolds number Re is 1.0× 104 with respect to the jet height L and the exit velocity U0. The Finite Volume Method （FVM） with orthogonal-mesh （6.17× 106 nodes） is used to discretize governing equations. The large eddies are obtained directly, while the small eddies are simulated by using the Dynamic Smagorinsky-Lily Model （DSLM） and the Dynamic Kinetic energy Subgrid-scale Model （DKSM）. Comparisons between computational results and experimental data show that the DKSM is especially effective in predicting the mean stream-wise velocity, the half-width of the velocity and the decay of the maximum velocity. The variations of the mean stream-wise velocity and the turbulent intensity at several positions are also obtained, and their distributions agree well with the measurements. The further analysis of dilute characteristics focuses on the tracer concentration, such as the distributions of the concentration （i.e., C / C0 or C / C,,）, the boundary layer thickness 6c and the half-width of the concentration b., the decay of the maximum concentration （ C / Co） along the downstream direction. The turbulence mechanism is also analyzed in some aspects, such as the coherent structure, the correlation function and the Probability Density Function （PDF） of the fluctuating velocity. The results show that the interaction between the two jets is strong near the jet exit and they are fully merged after a certain distance.

关键词： wall jet offset jet dilute characteristic coherent structure

ONE-AND TWO-DIMENSIONAL COUPLED HYDRODYNAMICS MODEL FOR DAM BREAK FLOW

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Journal of Hydrodynamics 2007年第6期19卷 769-775页

作者： YANG Fang-li ZHANG Xiao-feng TAN Guang-ming state key laboratory of water resources and hydropower engineering science Wuhan University Wuhan 430072 China

1-D and 2-D mathematical models for dam break flow were established and verified with the measured data in laboratory. The 1-D and 2-D models were then coupled, and used to simulate the dam break flow from the reservoir tail to the dam site, the propagation of dam break waves in the downstream channel, and the submergence of dam break flow in the downstream town with the hydrodynamics method. As a numerical example, the presented model was employed to simulate dam break flow of a hydropower station under construction. In simulation, different dam-break durations, upstream flows and water levels in front of dam were considered, and these influencing factors of dam break flow were analyzed, which could be referenced in planning and designing hydropower stations.

关键词： dam-break flow hydrodynamics model 1-D and 2-D coupled model dam-break duration upstream flow,water level before dam

Properties of Leakage Corrosion of Concrete and Its Durability

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Journal of wuhan university of Technology(Materials science) 2008年第6期23卷 946-949页

作者：戈雪良 Department of Materials and Structural engineering Nanjing Hydraulic Research Institute

The properties and mechanism of concrete under water leakage corrosion were studied in terms of the dissolution of calcium oxide and silicon oxide from concrete and the variation of pH value of permeate *** experimental results show that the amount of calcium oxide and silicon oxide dissolved from per cubic meter of concrete gradually decrease with penetration time and ultimately stabilize at a certain *** pH value of permeate water descend along with penetration *** durability of concrete under leakage corrosion was analyzed by a formula fitted on the dissolved amount of calcium oxide.

关键词： concrete leakage corrosion properties durability