• 全国中文核心期刊
  • 中国科技核心期刊
  • 美国工程索引(EI)收录期刊

2002 Vol. 13, No. 3

Display Method:
A mathematical model for unsteady sediment transport in the lower Yellow River, Ⅰ, model equations and numerical method
ZHANG Hong-wu, HUANG Yuan-dong, ZHAO Lian-jun, JIANG En-hui
2002, 13(3): 265-270.
Abstract:
A one-dimensional mathematical model for unsteady sediment transport in the lower Yellow River is developed In the model,the formulas of sediment carrying capacity and Manning roughness coefficient,which can reflect the features of two-phase flows in the Yellow River,are adopted.A saturation recovery coefficient is defined to represent the ratio between the bottom and the average concentration under the balance conditions,which is not a constant in this model and is evaluated by using an empirical expression obtained by integrating the sediment concentration along water depth.The concentration distributions and the mean diameter distributions of suspended sediment in the transversal direction are also est imated in this model.The Preissmann four point infinite difference scheme and algorithm for Tridiagonal Matrix Eqs.are employed in the numerical method.
A mathematical model for unsteady sediment transport in the lower Yellow River, Ⅱ, model verification
ZHANG Hong-wu, HUANG Yuan-dong, ZHAO Lian-jun, JIANG En-hui
2002, 13(3): 271-277.
Abstract:
The three typical floods occurring in 1977,1982,1996 in the lower Yellow River from Tiexie to Shunkou with a length of 393.67 km are numerically simulated by the established mathematical model for unsteady sediment transport.The computed results,such as the discharge,water stage,sediment concentra tion,cross sectional erosion and deposition,agree well with the observed data and validate therefore the mathemat ical model.
Numerical modeling of flood routing for the middle-lower Yangtze River system
HU Si-yi, SI Yong, WANG Ying-tan, WU Yong-xiang
2002, 13(3): 278-286.
Abstract:
In order to study flood management problems of the middle-lower Yangtze River system,a 1D-2D combined unsteady flow model is developed for simulating complex flood routing behaviors in the river-lake coupled system.A finite-volume method for computing 2D unsteady flows on an unstructured mesh is used to fit the complex configuration of the Dongting lake and to preserve mass balance; a 1D explicit-implicit-three-level difference scheme is applied to simulate branched and looped river network flows for accurately realizing automatic allocation of discharges at channel junctions and reversing flows.To increase modeling accuracy and extend modeling capacity,some essential problems arisen in the process of model building,including treatments of interior and exterior boundary conditions,flooding storage-discharge effects,and calculations of variable resistance terms,are discussed.Finally,the model is calibrated and verified against five flood events observed during 1954 - 1991 for illustrating excellent performances of this model.
A discrete numerical method for solving two-phase air-water flow equations
XI Cheng-gang, CHEN Jia-jun, XU Zhao-yi
2002, 13(3): 287-291.
Abstract:
A new numerical method for solving two phase air-water flow equations is developed The two phase air-water equations are solved with a finite element method.A discrete Newton iterative method is adopted to linearize the non-linear finite element equations after temporal and spatial discretion,it not only converges faster than the other methods,but also avoids the difficulties on programming.The mean of paralleling is adopted to solve the two-phase finite element equations,reducing much EMS memory needed in calculation by integrating means.
Experimental analysis of flexural strength and elastic modulus of the DUT-1 model ice
LI Zhi-jun, WANG Yong-xue, LI Guang-wei
2002, 13(3): 292-297.
Abstract:
The DUT-1 model ice is a new kind of synthetic model ice.Its characteristics,components and make processed are introduced.From a series of tests,the bending failures under different loading rates were obtained and the anisotropy behavior of the model ice was certified.It was found that its average flexural strength is 45 kPa and its average elastic modulus is 53.24 MPa.The flexural strength and elastic modulus increased with absorbed water amount and wetted density.Both became steady after water absorption 1 hour and kept the steady over 4 hours,which is longer enough for the performing model tests of ice interactions with structures and ice behavior.The ratio of elastic modulus and flexural strength was 82% over 2 000,which indicates that the DUT-1 model ice has the capability for the physical modeling tests in the scale of 1:10~1:30 based on Bohai ice flexural strength of 450~750 kPa.
Analysis on the characteristics of soil moisture transfer during freezing and thawing period
GUO Zhan-rong, JING En-chun, NIE Zhen-long, JIAO Peng-cheng, DONG Hua
2002, 13(3): 298-302.
Abstract:
The duration of freezing and thawing period almost accounts for a half year in the inland basin of northwestern China,in which the characteristics of soil moisture transfer is greatly differential from that of non-freezing period.Based on the observatory experiment on soil moisture transfer in inland plains,the distribution of soil moisture potential and the regularity of soil moisture ratio variation as well as its converting to groundwater during freezing and thawing period are analyzed.The significance of thawed water in eco-environment is also expounded.
A distributed model of reference evapotranspiration based on the DEM
NIU Zhen-guo, LI Bao-guo, ZHANG Feng-rong, CHEN Huan-wei
2002, 13(3): 303-307.
Abstract:
A distributed model for regional reference evapotranspiration was developed and applied for the daily simulation of evapotranspiration on August 28,2000 in Ordos sandland basin of the Kaokaolaigou river(area 114 km2).In the distributed evapotranspiration model,the radiation and vapour pressure strongly related to topography were adjusted firstly by utilizing GIS spatial analysis,then the spatial distribution of reference evapotranspiration was calculated and analyzed.Among the parameters,the temperature and wind speed were considered uniformity within the basin because of small variations in them.The result shows that the spatial variation of reference evapotranspiration is obvious because the radiation is depended highly on slope and aspect.The variation of reference evapotranspiration is increased with the enhancing spatial resolution of the model.The model is helpful for improving estimation of regional evapotranspiration,regional water balance study and distributed geographical model study and combating desertification.
Experiment study on the crop’s water-nitrogen production function
WANG Kang, SHEN Rong-kai, SHEN Yan-li, XU Cui-ping, QIN Qi-zhi
2002, 13(3): 308-312.
Abstract:
Crop water-nitrogen production functions were presented based on the crop's water production function theories and field water nitrogen interaction experiments.A final crop yield model and a dynamic crop yield model were studied in detail Parameters of the dynamic crop yield model were estimated from experimental data provided by J.J.Groot,the model was tested in Yongledian Beijing,and the good results were obtained.
Nitrogen wastewater irrigation study and its contamination risk analysis
LIU Ling, LU Gui-hua
2002, 13(3): 313-320.
Abstract:
Based on the nitrogen wastewater irrigation experiments carried out in the field experimental base,the movement and transformation regularities of nitrogen compound in wastewater irrigation were analyzed in this paper.The results showed that wastewater irrigation had a little influence on the ammonium concentration in deep-depth soil solution,but a big influence on the nitrate concentration in groundwater,especially in the soil with seriously wastewater irrigation before.The mathematical model,which was developed in the paper,could be used to predict the temporal and spatial distribution of ammonium-N and nitrate-N in soil solution and groundwater.The groundwater contamination risk analysis was conducted by using the Monte-Carlo simulation techniques.It is noteworthy that the maximum nitrate-N concentration at 5m depth of groundwater level is predicted to be great than 0.76 times of nitrate-N concentration in irrigated wastewater with 25% probability,and great than 0.43 times with 75% probability.Groundwater contamination risk should be considered in wastewater irrigation.
Research on the moving behaviors and modeling of light nonaqueous phase liquid in subsurface
ZHENG De-feng, ZHAO Yong-sheng, WANG Ben-de
2002, 13(3): 321-325.
Abstract:
A two-dimensional experimental chamber is designed and installed to simulate the spills or leaks of lighter than water nonaqueous liquid in water-wetted porous media.The results show the infiltration,movement and distribution of light nonaqueous phase liquid(LNAPL) in subsurface.Then the mechanisms of LNAPL contamination are analysed by the multiphase fluid theory.Based on the experimental results,the analytical models are developed to predict the moving behaviors of LNAPL in the unsaturated-saturated zone,including the spreading velocity of contaminant front in shallow vadose zone and the final extent of immobile oil lens.The calculated results are in good agreement with the experimental data.It is shown that the predict models are critical for control and remediation of LNAPL contamination in groundwater.
Environmental isotope study of the groundwater resources in the North Wulan-Buhe desert, Inner Mongolia
GU Wei-zu, LU Jia-ju, XIE Min, ZHANG Ru-zhi
2002, 13(3): 326-332.
Abstract:
The study area of about 4 200 km2 includes mainly the north part of the Wulan-Buhe Desert which is situated to the west of the Yellow River in Inner Mongolia,with an annual mean precipitation of 140 mm to 85 mm from its east to southwest.There are 68 sampling sites for groundwaters.In the relation δD=Sδ18O+d,S=8 and d=10 are get for the precipitation,it is just the same as the WMWL.For the groudwaters,the most δ18O values lie in the range of -7.4‰ to -12.1‰,the tritium content ranges from 0-190TU while the 14C values of 1.7-97 pMC are found.In comparison with the precipitation line,six kinds of groundwater with same or different A and d are found.From the isotopic relationships,four recharge sources are identified for the confined groundwater,i.e.,the paleogroundwater,the spring from fissued rocks of Lang Shan mountainous area situated to the northwest of the Desert,the percolation from the Yellow River,and the deep infiltration water from sand dunes which is formed by precipitation with special mechanism.Three source waters of phreatic groundwater are identified,too.They are the recent precipitation,the early episodic precipitation recharge and the water from sand dunes.The contribution of individual recharge source to the confined/phreatic groundwater at different places is estimated by using the mixing model.
Impact of human activities on salt water intrusion in estuaries
HAN Zeng-cui, PAN Cun-hong, SHI Ying-biao, XU You-cheng
2002, 13(3): 333-339.
Abstract:
Salt-water intrusion in estuaries depends mainly upon runoff,tide and riverbed configuration.These factors,however,will be changed under human activities,e.g.,low water discharge will increase due to the erection of a large-scale reservoir,and the tide range will be changed after training/reclamation in the estuary.Using the field chlorinity data recorded before and after those human activit ies and a 1-D mathemat ical model of salt-water intrusion,this paper analyses the impact of human activities on the saltwater intrusion in Qiantang River Estuary.The results from those two methods,the maximum,minimum and average chlorinity and the longest period of the days exceeding the chlorinity permissible standards,are basically identical.
Applications of the hybrid accelerating generic algorithm to parameter optimization of basin model
YANG Xiao-hua, LU Gui-hua, LI Jian-qiang
2002, 13(3): 340-344.
Abstract:
A hybrid accelerating genetic algorithm(HAGA) is presented by adding simplex searching operator and accelerate searching operator in real coding genetic algorithm.The HAGA is compared with some other genetic algorithms through some examples,and applied to the parameter optimization of the Daao basin model.The results show that this method has the features of direct,convenient,fast and good application.It is a superior non-linear optimal method which could locally search the global solution for greater probability.
Preliminary study on standard of riverway-digging effect forecasting
YANG Guo-lu, WU Hong-juan, YU Ming-hui, LI Ji-ze, WANG Chang-ci
2002, 13(3): 345-350.
Abstract:
Three judgement standards of riverway-digging effect forecasting,ratio of reducing deposit,speed of restoring and steady gradient,are put forward directed to the importance of riverway-digging effect forecasting.They are explained according to a mathematical model result combined with Shandong reach of Yellow River.Validity and application potent ial of riverway-digging effect are analyzed by the three judgement standards.
Study on application of the SD-MOP mix model to urban water resource planning of Qinghuangdao city
ZHENG Xue-hua, GUO Huai-cheng, ZHANG Bao-an
2002, 13(3): 351-357.
Abstract:
By applying the mix model of system dynamic multi-objective planning(SD-MOP) model,the article discussed the optimum uses of water resource in Qinhuangdao city.First,the overall development trends can be estimated based on the current development status,thus obtaining relevant information of water supply-demand.Second,according to the constraints of water resource emerged from the structural analyses of water use,the planning proposals of water use are formulated.Finally,by the running of the system dynamic model,the social,economic as well as the environmental responses are estimated reasonably based on the assumption of implementation of the formulated planning proposals.
Decision support system of optimum operation for the multi-purpose reservoir
SONG Song-bai, FENG Guo-zhang, WANG Shuang-yin, ZHOU Feng, LI Yi, WANG Xiao-wen
2002, 13(3): 358-362.
Abstract:
Taking the Shitouhe reservoir for example,this paper describes the principle and method of decision support system of optimum operation of reservoir for multi-purpose reservoir in detailed,and develops a decision support system of optimum operation for the Shitouhe reservoir.The system consists of 10 subsystem such as data collecting and transmitting,data management,hydrology forecast,drawing up using water plan,drawing up normal operation regulating plan,drawing up anti-flood operation regulating plan,making decision of normal operation regulating,making decision of antiflood operation regulating,optimum operation regulating and system maintain.
Numerical simulation of energy dissipator flow field for Shilianghe reservoir
WANG Ling-ling, YAN Zhong-ming
2002, 13(3): 363-367.
Abstract:
Energy dissipator flow is a kind of strong turbulent two dimensional flow with unsteady free surface.In this paper,a double-equation model incorporating the method of curvature correction is developed to closure the Reynolds stress and the SIMPLEC scheme is used to discrete turbulent governing equation.The numerical model is applied to simulate the Shilianghe project energy dissipator unsteady flow field.The computed results give out rational characteristics of turbulence-vortex and bumping of free surface,are agrees with the experimental results,and show that the model is effective and practical to solve similar engineering problems.
Fractal, self-organization and its physical mechanism of river networks
WANG Fu-quan, CAO Shu-you, DING Jing
2002, 13(3): 368-376.
Abstract:
This paper briefly introduces and reviews the achievements of fractal and self-organization of river networks,points out existing questions in the articles and possible improvement ways at the same time,discusses the physical mechanism of production and evolution of the self-organized fractal structure of river networks from the viewpoint of internal and external force of the earth as well as the opening property,the nonlinear property,the stochastic property and the dissipative property of the river network system,and proposes the further study projects in the field of basin erosion and ecosystem restoring,flow production and flow together of the basin,sediment production and transport,the evolution of the riverbed form and so on.
Thinking of integrated management of urban rivers in China
SONG Qing-hui, YANG Zhi-feng
2002, 13(3): 377-382.
Abstract:
The advances on river management in developed countries are introduced and discussed in this paper.By analyzing the existing problems in urban river management and harness in China,the necessarity of changing the notion of urban river management and reforming the harness techniques are put forward.It is also pointed out that the tendency of integrated management of urban rivers are as follows:①assuring the land for river,②introducing the idea basing on human in river planning,③recovering the biodiversity,landscape diversity and environmental self-cleaning capacity of river,④researching and applying the multiple natural river technique harnessing the river,and ⑤building the sociable management mechanism for the urban river.
Analysis on polluted causes and their maintainable strategies of municipal slow-flow water bodies
ZHU Liang, CAI Jin-bang, CHEN Yan
2002, 13(3): 383-388.
Abstract:
Based on the discussion on the moving characteristics,the hydrochemical process and the pollution sources of the municipal slow-flow water bodies,this paper proposed some countermeasures to preserve municipal slow-flow water bodies,such as the establishment of a scientific nanagement system of municipal water affairs,the combination of the municipal water engineering with the ecological engineering,the full use of the function of water engineering in the protection of municipal water bodyes and the perfect integrated ways of controlling the storm and sewage.
Research situation and prospect of the soil erosion model
ZHANG Guang-hui
2002, 13(3): 389-396.
Abstract:
Soil erosion is one of most serious environmental issues.It's very important to build soil erosion model for prediction of soil and water loss,design soil and water conservation measure,and utilize water and land resources.The develop history,research situation,and existing problems for both experiential and process-based soil erosion mode were summarized in this paper.The detailed prospects were given in the aspects of research method,research fields,which need be strengthen,variation of parameters,demonstration for erosion model,and possibility of combining erosion model building with GIS,Remote Sense,and tracer element.The object of this paper was to make the summary of the research experience of soil erosion model and promote the development of soil erosion model in China.