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Numerical Simulation of water-Air Two-Phase Flow in Soil Slope under water Level Rise Condition

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Wuhan university Journal of Natural Sciences 2009年第5期14卷 442-446页

作者： ZHANG Xiaoyue,ZHU Yueming,FANG Chunhui,CHEN Shoukai college of water Conservancy and hydropower engineering,hohai university,nanjing 210098,Jiangsu,china college of water Conservancy and hydropower engineering Hohai University Nanjing China

In order to simulate the unsteady seepage in soil slopes under water level rise condition, including water seepage and air seepage, and to investigate the influence of the capillary pressure on the slope safety coefficient, the water-air two-phase flow model was used and its solving method and definition condition were given. By the two-phase flow model, the pore air and pore water seepage of a soil slope under steady seepage and water level rise conditions were shown, and the slope stability in different cases was analyzed from the simulation results. We find that under water level rise condition, the pore air pressure in the unsaturated zone increased evidently and the capillary pressure should be considered while the pore air pressure can be neglected in slope stability analysis.

关键词： water-air two-phase flow water level rise saturated-unsaturated seepage capillary pressure slope stability

Dam risk assistant analysis system design

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Science china(Technological Sciences) 2008年第S2期51卷 101-109页

作者： HE XianFeng1,2,3,GU ChongShi3,4,WU ZhongRu3,4 & SU HuaiZhi3,4 1 Yellow River Institute of Hydraulic Research,Zhengzhou 450003,china 2 Embankment Security Defect Prevention and Control engineering Research Center of MWR,Zhengzhou 45000,china 3 college of water Resources and hydropower engineering,hohai university,nanjing 210098,china 4 National engineering Research Center of water Resources Efficient Utilization and engineering Safety,hohai university,nanjing 210098,china Yellow River Institute of Hydraulic Research Zhengzhou China Embankment Security Defect Prevention and Control engineering Research Center of MWR Zhengzhou China college of water Resources and hydropower engineering Hohai University Nanjing China National engineering Research Center of water Resources Efficient Utilization and engineering Safety Hohai University Nanjing China

In order to reduce the labor intensity and task difficulty of dam risk analysis and to meet the actual requirement of dam risk analysis,it is necessary to establish a dam risk assistant analysis *** program structure and the implementation ways of the dam risk assistant analysis system are analyzed,and a procedural framework with "three-tier and multi-database" structure and "level structure" is *** concept of dam risk assessment system modular development is proposed and the coupled mode of function module and data is ***,the dam risk assistant analysis system is developed using Delphi visual programming language.

关键词： dam risk risk analysis assistant analysis system

NEW METHOD OF SIMULATING CONCENTRATED DRAIN HOLES IN SEEPAGE CONTROL ANALYSIS

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Journal of Hydrodynamics 1999年第3期11卷 27-35页

作者： Zhan Mei li, Su Bao yu , Liu Jun yong, Shen Zhen zhong college of water Conservancy and hydropower engineering, hohai university, nanjing 210098, P.R.china (Received Aug.1, 1998)

In this paper, based upon the basic solution of sink, the approximate solution of single drain hole in finite elements is derived by use of the superposition principle. Then, the theoretical solution is extended to the case of some drain holes in one finite element, and the method is used in seepage control analysis with quick convergence and high accuracy. On the other hand, if the positions of the drain holes are changed, only some control factors of drain holes are changed, but the finite element grid need not to be reformed. Therefore, the method is more suitable in optimal research of seepage control.

关键词： concentrated drain hole approximate solution seepage control optimal research

EXPERIMENTAL STUDY AND NUMERICAL SIMULATION OF FLUORIDE IN SAND

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Journal of Hydrodynamics 2006年第6期18卷 748-751页

作者： ZHANG Hong-mei SU Bao-yu School of Resources and Safety engineering China University of Mining and Technology Beijing 100083China college Of water Conservancy and hydropower engineering Hohai University Nanjing 210098China

The transport and transformation of fluoride in sand were studied by using soil tank test under the condition of saturated water in this article. Based on the analysis of the laboratory experiments, the rules of fluorine transportation and transformation were simulated in sand by solving the advection-diffusion equation. Through comparison between computed results and observed data , it is shown that the established model and determined parameters could be used to simulate the fluoride transport in sand.

关键词： sand fluoride dynamic test numerical simulation

INFLUENCE OF FILLING water ON AIR CONCENTRATION

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Journal of Hydrodynamics 2011年第5期23卷 601-606页

作者： WU Jian-hua MA Fei DAI Hui-chao college of water Conservancy and hydropower engineering Hohai University Nanjing 210098 China

The filling water inside the cavity below an aerator occurs for the flow of low Froude number or the small bottom slope of a spillway. The aerator may cease to protect against cavitation damages, and may even act as a generator of cavitation if it is fully filled by water. The experiments were conducted to investigate the influences of the geometric parameters, and then the filling water on the air concentration. The results show that the filling water, or the net cavity length, is closely related to the plunging jet length for a given aerator, and the air concentration at some section is proportional to the ratio Ln/Lj at a fixed Lj for different geometric parameters of aerators. Secondly, at the same ratio of Ln / Lj, the aerator with a larger height or a larger angle of ramp, or a larger bottom slope, would have a larger plunging jet length, and then a larger net cavity length based on the ratio of Ln / Lj. As a result, the large space of cavity, or the high air concentration of the flow could be obtained although the filling water increases also based on the fact that Lf = Lj - Ln. It is the space of the cavity that is the dominant factor to affect the air concentration of the flow.

关键词： aerator air concentration filling water jet length net cavity length

HYDRODYNAMIC CHARACTERISTICS OF CHINESE STURGEON SPAWNING GROUND IN YANGTZE RIVER

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Journal of Hydrodynamics 2008年第2期20卷 225-230页

作者： YANG Yu YAN Zhong--min CHANG Jian-bo nanjing Hydraulic Research Institute Nanjing 210029 China State Key Laboratory of Hydrology-water Resources and Hydraulic engineering Nanjing 210029 China college of water Conservancy and hydropower engineering Hohai University Nanjing 210098 China Institute of Hydro-ecology Wuhan 430072 China

Since the construction of the Gezhouba Dam on the Yangtze River in 1981, it has been found that the Chinese Sturgeon, Acipensor sinensis, performs natural propagation annually in a narrow reach downstream close to the Gezhouba Dam site. This might allow one to better investigate the river hydrodynamic conditions of the Chinese Sturgeon spawning ground. In this article, spatial Kinetic Energy Gradient （KEG） and absolute value of vorticity were computed along the river sections from measured data. The relation between Spawn Density per Unit Area （SDUA） and vorticity strength and between SDUA and KEG were worked out. The Results showed that the vorticity and KEG were both effective parameters for describing the hydrodynamic characteristics of Chinese Sturgeon spawning ground. The Chinese Sturgeons prefer to spawn in the river sections where the value of vorticity strength is larger than 0.4 s^-1 and KEG is larger than 0.029 Jkg^-1m^-1.

关键词： hydrodynamic characteristics Chinese Sturgeon spawning ground vorticity kinetic energy gradient Spawn Densityper Unit Area (SDUA)

THREE-DIMENSIONAL SIMULATION FOR EFFECTS OF BED DISCORDANCE ON FLOW DYNAMICS AT Y-SHAPED OPEN CHANNEL CONFLUENCES

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Journal of Hydrodynamics 2007年第5期19卷 587-593页

作者： WANG Xiao-gang YAN Zhong-min GUO Wei-dong college of water Conservancy and hydropower engineering Hohai University Nanjing 210098 China college of water Conservancy Shenyang Agricultural University Shenyang 110161 China

Channel confluences are universally present in nature. They can be divided into two types： asymmetrical river confluences and symmetric river confluences. The latter is also called as the Y-shaped confluences. Most of previous work has paid more attention to the asymmetrical river confluences, but few studies have been conducted on the Y-shaped confluences. In this article, the effects of bed discordance on the flow patterns at ＂Y＂ shaped open-channel confluences were studied by using a 3-D numerical simulation. It is proved that the model can undertake quantitative assessment of the flow at confluences. The results indicate that there are a lot of differences between the Y-shaped confluence and asymmetrical confluence. The discordant bed height plays an important role at the Y-shaped junction.

关键词： Y-shaped junction discordant bed height,separation zone numerical simulation turbulent intensity,secondary flow lateral mixing

COUPLING EFFECT OF SEEPAGE FLOW AND RIVER FLOW ON THE BANK FAILURE

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Journal of Hydrodynamics 2011年第6期23卷 834-840页

作者： NING Bo WU- Shi-qiang TAN Ye-fei XIE Xing-hua YAN Jun YAN Zhong-min GENG Yan-qiong college of water Conservancy and hydropower engineering Hohai University Nanjing 210098 China nanjing Hydraulic Research Institute Nanjing 2100-29 China nanjing Hydraulic Research Institute.nanjing 210029 China Lian Yungang Technical college Lian Yungang 222000 China

On the basis of the generalized physical model of the riverbank, the experiments were conducted to study the mechanisms of riverbank failure under the coupling effect of seepage flow and river flow. The experimental setup was specially designed, as well as test point location, parameters and procedures, and the main influencing factors were analyzed affecting riverbank failure based on the failure types, the variations of pore water pressure and soil displacement. The results indicated that the coupling effect has different influences on the bank failure in three aspects： the failure type, the process and the extent. In addition, the river flow played a more important role than the seepage flow in the coupling effect on the bank failure.

关键词： bank failure seepage flow river flow physical model test

Effects of Bahia Grass Cover and Mulch on Runoff and Sediment Yield of Sloping Red Soil in Southern china

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Pedosphere 2011年第2期21卷 238-243页

作者： LI Xin-Hu ZHANG Zhan-Yu YANG Jie ZHANG Guo-Hua WANG Bin college of water Conservancy and hydropower engineering Hohai University Nanjing 210098 (China) Key Laboratory of Efficient Irrigation-Drainage and Agricultural Soil hohai university Nanjing 210098 (China) Jiangxi Institute of Soil and water conservation Nanchan9 330029 (China) china Irrigation and Drainage Development Center Beijing 100054 (China) college of water Conservancy and Building engineering Northeast Agricultural University Harbin 150030 (China)

Rainfall,runoff (surface runoff,interflow and groundwater runoff) and soil loss from 5 m × 15 m plots were recorded for 5 years (2001-2005) in an experiment with three treatments (cover,mulch and bare ground) on sloping red soil in southern *** runoff and erosion from the Bahia grass (Paspalum notatum Flugge) cover plot (A) and mulch plot (B) during the 5 years were low,despite the occurrence of potentially erosive *** contrast,the bare plot (C) had both the highest surface runoff coefficient and the highest sediment *** were significant differences in interflow and surface runoff and no significant difference in groundwater runoff among *** runoff coefficients and duration of interflow and groundwater runoff were in the order plot B > plot A > plot *** of Bahia grass cover were excellent,indicating that the use of Bahia grass cover can be a simple and feasible practice for soil and water conservation on sloping red soil in the region.

关键词： groundwater runoff interflow lysimeter soil properties surface runoff