• 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

2000 Vol. 11, No. 4

Display Method:
A New Finite Volume Method for Two Dimensional Convection-Diffusion Problems
JIANG Chun-bo, DU Li-hui
2000, 11(4): 351-356.
Abstract:
The finite element formulation and the finite volume form ulation are compared,both formulations are conservative and the finite volume scheme is a special kind of the finite element scheme.A new finite volume scheme is proposed by modifying the time derivative term on a control volume and by using the fractional time step integration.The one dimensional purely convection flow and two dimensional convection-diffusion flow are computed by this scheme,the results are compared with the analytical solution and the finite element simulation,which shows that the present finite volume scheme has good accuracy and stability properties.
Numerical Simulation of Turbulent Flow around Bluff Bodies Using the RNG κ-ε Turbulent Model
LI Ling, LI Yu-liang
2000, 11(4): 357-361.
Abstract:
In this paper the RNG κ-ε Turbulent Model is applied to simulate the turbulent flow around bluff bodies.The incompressible N-S equations are solved in a non-orthogonal curvilinear system by the finite volume method with a nonstaggered grid.The results are compared with experimental data.It is shown that the RNG κ-ε Turbulent Model can be used to simulate wake flow relative time.
A Lattice BGK Model for Simulating One-Dimensional Unsteady Open Channel Flows
CHENG Yong-guang, SUO Li-sheng
2000, 11(4): 362-367.
Abstract:
A lattice BGK model for one-dimensional unsteady open channel flows is established by analyzing the multi-scale equation s of the LB method and St.Venant equations.Some classical and practical flows,such as unsteady open channel flows in head races of hydropower plants and dam break waves,are simulated by the LB scheme.The LB results are in good agreement with the results of implicit Preissmann scheme and the method of characteristics.It is shown that the LB method is a fea sible and accurate approach to simulate one-dimensional unsteady open channel flows in engineering.
Finite Volume Method and Riemann Solver for Depth-Averaged Two-Dimensional Flow-Pollutants Coupled Model
ZHAO Di-hua, QI Chen, YU Wei-de, XU Bao-hua, PEI Zhong-ping
2000, 11(4): 368-374.
Abstract:
A depth-averaged two-dimen sional flow-pollutants coupled model is developed to evaluate impacts of industrial effluents and domestic waste on water environment.Developed in the framework of finite volume method on an unstructured grid,the model transfers 2-D problem in to solving a series of local 1-D problem.It takes the merits of the finited ifference method and the finite element method.The model employs Osher-type approximate Riemann solver to estimate the numerical flux of variables across the interface between cells with high accuracy.The model can be applied to the unsteady and steady stated as well as the subcritical and supercritical flowregimes.The model was examined by several samples with exact solutions.The comparison between computed results and exact solutions demonstrates very good agreement.Finally,the model was applied to water quality simulation in Hanjiang River.The simulated polluted area is matched well with observations.
Study on Effect Factors of Water Environmental Capacity for Tidal River Network
XU Gui-quan, CHU Jun-da, WU Zu-yang, CHEN Qing-jiang
2000, 11(4): 375-380.
Abstract:
The primary factors affecting water environmental capacity for tidal river network,such as tide,storage capacity,water conservancy project,pollutants decay coefficients and boundary water quality of drawing water,were studied in this paper.Based on the water quality model for tidal river network,the computational method of aquatic environmental capacity was improved.The time-space changing law of the influence of above factors on aquatic environmental capacity was studied by the example of the river network of Punandong Area in Shanghai,and then the permitted pollutants discha rgeamount was put forward.
Research on the Flow Field Characteristics of the Near Wakes Behind 2-D Peninsulas
LIANG Dong-fang, LI Yu-liang, TIAN Xiao-dong
2000, 11(4): 381-386.
Abstract:
By applying Digital Particle Image Velocimetry (DPIV) technique,velocity fields in the near wakes behind semicircular and sinusoidal shaped peninsulas in constant inlet flow are measured in detail respectively,and a large number of quantitative data are acquired.This paper puts enough emphasis on the similarity in analyzing the mean velocity over a long period of time (where the long period is referred to as a cycle of the Karman Vortex Shedding).In this way we attempt to find out some disciplines of the velocity distribution in this region.The averaged velocity distribution in each transect seems to approximately obey the similarity law after normalization,but the turbulent parameters distributions are quite different.
The Correlation Coefficient Extreme Value Method to Determine the Dispersion Parameters of River
GUO Jian-qing, WANG Hong-sheng, LI Yun-feng
2000, 11(4): 387-391.
Abstract:
By logarithmic tran sformation of the analytic solutions expressing one-dimension water masstracer dispersion test with instant injection of tracer,a linea requation,whose independent variable X includes test data t and x,u with unknown value,dependent Y includes the test data c and t,and the linear constants include the long itudinal dispersion coefficient D,was derived.A ccording to the p inciple that the suitab levalue of u should make the value of correlation coefficient between Y and X extreme,the equation computing the value of u was derived.With known the value of u,the values of X correspond ingto different observation time may be computed.Then the linear constants may be determined by the method of linear regression to analyze the data of Y-X,and finally the dispersion parameters can be estimated.
Transfer Function Model on Chloride Transport in Heterogeneous Saturated Soils under Steady Flow
REN Li, WANG Ji, QIN Yao-dong
2000, 11(4): 392-400.
Abstract:
The experiments were done for the purpose of analyzing saturated solute transport in the heterogeneous soil.Two kinds of heterogeneous soil columns (48cm×48cm×40cm) were irrigated with 0.027 Mol/L CaCl2 solution when steady flow occurred in the soils.The breakth rough curves data were obtained.The parameters of the model were calculated,and the probability density functions of the logarithm of travel time of chloride were derived.In addition,the simulated data of breakthrough curve of the chloride in heterogeneous soil were computed using the transfer functionm odel.Finally,the transport volumes of Cl-,mobile volume and the volume-averaged concentrations in the soil solution were estimated.
Effect of Sorption on Organic Biodegradation in Soil/Water System
LIU Ling, CUI Guang-bai
2000, 11(4): 401-407.
Abstract:
The sorption has major influence on organic pollutant biodeg radation in soil/water system.It is found that the bioavailability of organic pollutant,as well as the fraction of organic pollutant exists in the aqueous phase at sorption equilibium,decreases along with the increase of soil-water partition coefficient Kd,or the increase of soil-water ratioin the system.A spherical model has been developed in this paper in order to describe quantitatively the effect of sorption on the transport of organic pollutant in side the soil particle.It is noteworthy that the overall organic biodegradation rate in the system is controlled by its sorption capacity.Chemical with a large Kd value with chemical will have low transport rate and low biodeg radation rate in soil/water system.
Spatial Varibility of the Regional Shallow Groundwater Depth and Water Quality
HU Ke-lin, LI Bao-guo, CHEN De-li
2000, 11(4): 408-414.
Abstract:
139 observing points were sampled in Quzhou County in Huabeiplain.The depth of groundwater,salt and nitrate content of groundwater were measured.The geostatistics theory was applied to analyze the data.The results indicated that the depth of groundwater showed a normal distribu tion,the salt content showed a lognormal distribution and the nitrate content showed neither a normal nor a lognormal distribution.The rational sampling number was determined within a given precision at a known confidence level.By the semivariance analysis those observ items were correlated in a given spatial range.The Kriging method was applied to estimate the unobserved points and generate the contourmap.These results show some merit in rational using the groundw ater resource and preventing soil secondary salinization and the nitrate pollution.
Relationship between the Formation of Groundwater and the Evolution of Regional Hydrologic Cycle in North China Plain
ZHANG Guang-hui, CHEN Zong-yu, FEI Yu-hong
2000, 11(4): 415-420.
Abstract:
The formation of groundwater is closely related with the evolution of regional hydrologic cycle in periodicity in North China Plain since the last phase of the Pleistocene.The revival capacity of regional groundwater depends fundamentally on the evolutional course of the regional hydrologic cycle.The recharge of groundwater is sufficient in rainy period and is less so that the groundwater level and the sea surface decline in rain less period of the regional hydrologic cycle course.The latent capacity of utilizing groundwater is variable,which depends on the land processes of the regional hydrologic cycle.The land processes are adjusted to rise the utilization ratio.
Analysis of Spatial Variability and Monitoring Error of Soil Moisture
LI Guo-fang, XIA Zi-qiang, HAO Zhen-chun, JIANG Hong-geng, CHEN Hai-fang
2000, 11(4): 421-426.
Abstract:
On the base of the situ data,the spatial variability of soil-water content and its influece factors are analysed,the correlation between monitoring error and spatial variability,and the correlation between monitoring error and sampling number are discussed.The result shows that the error decreases with the rise of sampling number,and rises with the rise of spatial variability.The determination of necessary sampling number is also discussed.
Application of the Neural Network Theory to the Flood Prediction
LI Rong, LI Yi-tian
2000, 11(4): 427-431.
Abstract:
Flood evolution exhibits a complicated non-linear dynamical process.The neural network possesses the capability of dealing with complexnon-linear dynamical systems,this paper demonstates howit can be used in flood prediction as a new approach considering the non-linear relation ship between flood evolution and its factors such as discharge,channel deformation,and so on.Based on it,the neural network approach is applied to the flow prediction of Yangtze Riverat Luoshan station.The preliminary results suggest that the phenomenon of small discharge with high level in middle reaches of Yangtse River recently,especially in 1998,is related to the downstream aggregation.And the quantitative relations between the water level variation of Luoshan station and the downstream aggregation are obtained.
Study on Estimating Index of Flood Damage
FU Xiang, JI Chang-ming
2000, 11(4): 432-435.
Abstract:
Based on analyzing the charcterstics of flood damage estimation,the paper establishes uniform estimating index of flood damage.The index consists of personal casualty damage,economic property damage,ecoenvironment damage,and hazard relief damage.A scientific and systemic estimation method is provided for reflecting entirely the situation of flood hazard.
Study on the Principle of the Sustainable Ultilization of Water Resources (Ecological Hydraulic Engineering)
FU Chun, FENG Shang-you
2000, 11(4): 436-440.
Abstract:
This paper aims to inquire into the principle of the sustainable ultilization in the sust ainable development of water resources (ecological hydraulic engineering).Firstly,The concept and the defining of the sustainable ultilization of water resources is gave.Secondly,the principle and the meaning of four links for the entirety,the coordination,the optimization and the good cycle are indicated.At last the mathematics models about sustainable ultilization of water resources is discussed.
Using the Object Oriented Program to Research and Develop the Water Dispatching Decision Suport System
WANG Yu, YANG Li-bin, HOU Chuan-he, WANG Dao-xi, HU Yong-sheng
2000, 11(4): 441-446.
Abstract:
The Object Oriented Program (OOP) has changed the methodology of system analysis,system design and system development,increasing the efficiency of development and convenience of maintenance.With the application of OOP and Visual FoxPro and Visual Basic,the development of Water Dispatching DSS is more efficient,the interface is more friendly and the extension of the system is easier.The OOP is one of the efficient methods to develop the decision support system.
Establishment and Operation of the Automatic System of Hydrological Data Acquisition and Transmission of Electric Power Plant in China
SHUN Qin-fang, PEI Zhe-yi
2000, 11(4): 447-450.
Abstract:
In this paper the establishment and operation of automatic system of hydroelectricity data acquisition and transmission (ASHDAT) in China are analyzed,the index of ASHDAT are analyzed,the benefits of ASHAT in the flood control and hydroelectrcity generation are summarized,and the present problems and suggestions for the future are put forward.
A New Time Serial Synthetical Analysis Method
LI Ling, SHI Yong
2000, 11(4): 451-456.
Abstract:
Based on the traditional method of time serial analysis,a new model of GM (1,1) is adopted and a mathematics model is built by combining the analysis method with the grays theory.When applied the model to the monthly discharge for ecasting of Bengful,Fengshan and other stations in 1985,the results are satisfactory.
A Review of Study on Fractals of Soil Hydraulic Properties
ZHAN Wei-hua, HUANG Guan-hua
2000, 11(4): 457-462.
Abstract:
In this paper,describing soil structure and characterizing soil hydraulic properties with fractal theory are reviewed since 1980s.Based on the theory,the fractals of porous media are characterized by fractal dimensions of soil pores,particle-size distribution and particle surface or volume of soils,and the fractal models of soil water retention characteristics and hydraulic conductivity are determined accordingly.Also the advances of fractal theory in hydraulic properties are discussed.
A Review of the Digital Elevation Model Extraction and Digital Hydrological Modeling
REN Li-liang, LIU Xin-ren
2000, 11(4): 463-469.
Abstract:
In this paper,the methodology of drainage network extraction from grid-based the digital elevation model (DEM) is reviewed.Then the current situation of application of information extracted from a DEM data in the field of hydrology and water resources are remarked.It is shown that the digital model plays a great role in datamining in hydrology and water resources.Water-related datamea sured at gaugedstations could be assimilated to areal information over a catchment by the digital model,so as to serve for all trades and professions of national economy.Finally the position and the perspective of the digital hydrology (DH) in digital earth are discussed.The DH is an important component of digital earth.It needs further research.
When Will Fresh Water Use in China Reach the Climax?
JIA Shao-feng, ZHANG Shi-feng
2000, 11(4): 470-477.
Abstract:
China is a country of serious water shortage.Future water demand forecast is very important for policies-and-decision-makers to design water supply and demand balance measures and to direct indurtrial location.How about the future trends of water use in China? All the previous studies showed that the water use will continuc to increase until year 2030 or even later to 2080 and the highest water demand reach 700~900 billion cubic meters which is 150~350 billion cubic meters more than recent water use.If so,China will face more serious water short age problem.This paper put for ward a completely different opinion on the future water use trends of China.The water use(meaning fresh water with drawhere) will reach the maxiouum in 10 years because of the following 5 reasons.The first,the water use increase rate in China does already slow down(about 1% a year).The second,China will lift water supply price which is much lower than cost at present and the violently rising water supply price will obstruct the increase of water use.The third,the industrial structural upgrade especially the stagnation and sliding down of heavy industries such as iron and steel industry will cut down industrial water demand.The fourth,Stricter environmental protection regulations and stricter execution of those regulations will oppress the fresh water demand.The fifth,in South China we don't have more arable land to be irrigated while in North China we don't have more fresh water resource to be wihdrawn.