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High accuracy simulation for propagation
and diffraction of Dam-break waves
Wang Jiasong Ni Hangen Jin Sheng
Abstract A high resolution difference model for 2-D shallow water flow
equations is presented in this paper.The second order hybrid TVD scheme with Van Leer's
MUSCL limiters is applied along x and y direction splitted from shallow flow equations.To
verify its validity,the scheme is applied to solve 1-D and 2-D dam-break problems.The
numerical results are compared with the theoretical exact solution and other numerical
methods.It demonstrates that the method is successful.The propagation and diffraction of
dam-break wave a round a rectangular cylinder is also simulated in the case of the dam
either fully or partly broken.It gives very satisfactory results and reveals the
complicated flow characteristics of the wave.
Key words shallow water flow
equation,2-D dam-break waves,second order TVD scheme.
Liu Haiqing Zhao Zidan Zhang Qinghe
Abstract The propagation of waves passing over the
abrupt changing topograghy can be simplified as a wave passing over a step.This flow
process can be reasonably simulated by a 2-D numerical wave flume developed in this
paper,especially for the nonlinear transformation of the wave on the step.Numerical
results have been verified by experimental data.
Key words numerical wave flume,finite element method,step
topograghy,boundary condition.
Degradation and stability
of soft soil site under wave loading
Wang Jianhua Chen Cheng Zhang
Qinghe Lian Jijian
Abstract In this paper the
visco-elasticity constitution relationship of cyclic degradation describing offshore soft
clay behaviors is studied.A method for quantitatively analyzing the stability of offshore
soft soil sites under wave loading is developed by combining the relationship with
water-mud multi-layer interface model.Since the variation of nonlinear visco-elasticity
parameters due to cyclic degradation of soft clay can be considered,the analytic results
can reflect the changing process of soft clay under wave loading.
Key words soil dynamics,offshore soil mechanics,stability of offshore sites.
Shape optimization of arch dam subject
to crack-depth contraint
Sun Linsong Wang Dexin Sun Wenjun
Abstract In this paper the mathematical
model for shape optimization of arch dam subject to crack-depth constraint is estabilshed
and the super finite element method(SFEM) for arch dam cracking analysis is used as the
re-analysis method.The research findings on Xiaowen Arch Dam show that the shape
optimization of arch dam subject to crack-depth constraint may further help reduce the
volume of dam.
Key words arch dam,crack-depth constraint,shape optimum design,SFEM.
Automatic Generation of Contour in
Triangule Mesh and its Programming
Chang Jianmei Chen Chongxi
(The fourth Survey and Design Institute,Ministry of Railway)
Abstract The theory and the
approach to trace the contours in triangular mesh are presented in detail in this
paper.The programming realization and the function of contour package developed by the
authors are also introduced which can be applied to groundwater finite element simulation
and other fields.
Key words triangular mesh,interpolation,contour tracing,contour package.
Using Fourier transforms to
express sprinkler overlapping uniformity
Zhu Dansheng
(Gansu Pilot Irrigation Project)
Liu Jiali
(Water Conservancy Research Institute,Gansu)
Abstract Various Fourier
transforms have been applied to investigate the new calculation method for sprinkler
overlapping uniformity.The uniformity coefficient is described by a mathematical
expression with parameters including water distribution,spacing,orientation,etc.The result
of an example is compared with the observation data.It demonstrates that the new method is
feasible for practical use.
Key words Fourier Transforms,overlapping uniformity,profile form distribution of sprinkler.
Correlation analysis and application
of precipitation infiltration coefficient
and stratum area weight
Abstract According to the base
flow separation results from hydrographs in many watershed,the best regression equation
expressing the relationship between annual precipitation infiltration coefficient and the
weight of different strata area to total area of the watershed is established.The equation
can be used to calculate the precipitation infiltration recharge for different ground
water basins in which the strata distribution and the precipitation are given.The
precipitation recharge is equivalent to the ground water recharge in some mountainous area
where the exploitation of ground water resources are far from being sufficient.
Key words precipitation recharge coefficient,area weight of different stratum,regression
analysis.
Determination
of daily evaporation and evapotranspiration of winter
wheat field by large-scale weighing lysimeter and micro lysimeter
Liu Changming Zhang Xiying You
Maozheng
(Institute of Agricultural modernization at Shijiazhuang
and United Research center for Water Problems, CAS)
Abstract The large-scale weighing
lysimeter and micro lysimeter are employed to determine the daily alteration processes of
evapotranspiration and soil evaporation of winter wheat in its growth stages. According to
the observation data, the authors found that about 30% of the total field
evapotranspiration is consumed by the soil evaporation under canopy. Furthermore, the
water-saving farming can be expressed as increasing leaf area index (LAI) in the early
stage of growth and controlling topsoil moisture under the canopy. Based on the
evapotranspiration determination the dimensionless crop coefficient can be calculated.
Key words large-scale lysimeter, micro lysimeter, winter wheat, evapotranspiration,
evaporation.
Iteration method of nonlinear regression
and its application
to ground water studies
Qi Rengui
(Institute of Water Conservancy, Henan Province)
Abstract The mathematical
principle of using iteration method to solve the nonlinear regression problem is discussed
in this paper. The pure nonlinear regression problem can not be solved by minimum double
multiplication. The iteration method is applied to study on ground water. Results show
that the method is easy for use and yields high precision.
Key words nonlinear regression, iteration method, minimum double
multiplication, ground water.
The Green-Ampt model
and infiltration characteristics of surge
flow irrigation for muddy water
Wang Zhirong Wang Wenyan Wang
Quanjiu Fei Liangjun Zhang Jianfeng
(Xian University of technology)
Abstract Based on the data of
surge and continuous flow infiltration of muddy water with five sand content in loess
region, the applicability of Green-Ampt equation is analyzed. The relationship for
infiltration between surge flow and continuous flow are found. The methods for determining
the parameters of the equation are discussed. Moreover, a good agreement of the
calculation result with the observation data is obtained.
Key words surge flow, infiltration, Green-Ampt model, muddy water.
Mechanism and effect of
silt-arrest dams for sediment
reduction in the middle Yellow River basin
Fang Xuemin, Wan Zhaohui, and
Kuang Shangfu
(China Institute of Water Resources and Hdropower Research)
Abstract The influences of silt-arrest
dams to runoff process and sediment transport are analyzed. The characteristics of
sedimentation and mechanism of sediment retaining are discussed. The effects of
silt-arrest dams to sediment reduction are studied with consideration of sediment
retaining capacity, long term variation of sediment load and typical storms and floods
etc.
Key words silt-arrest dam, soil conservation, sediment reduction, the Yellow River.
Study on 2－D plane wall jet in static circumstances
Duan Wenzhong
(Wuhan University of Hydraulic and Electric Engineering)
Zhang Zhengquan
(Yangtze River Scientific Research Institute)
Abstract On the basis of theoretical
analyses, the relationships among change of momentum flux of the 2-D plane wall jet, loss
of wall shear stress and its momentum flux, change of velocity and discharge along the
flow course are established in this paper. The validity of these relationship are verified
by observation data.
Key words wall jet, wall shear stress, momentum loss, velocity distribution.
Study on 2-D mathematical
model of water and sediment
movement at the branch river estuary
Lu Yongjun
(Tianjin Institute of Water transport Engineering, Ministry of Communication)
Abstract A 2-D mathematical model of water
and sediment movement at the river estuary is established. Because of the complicated
boundary conditions at the confluence, the goveming equations and numerical simulation of
total sediment load are given in the boundary-fitting orthogonal coordinate systems. By
using this model, the characteristics of water and sediment as well as the cause of shoal
at the confluence of Jialingjiang estuary on the upstream reach of the Yangtze River are
analyzed. The velocity field and the erosion and deposition distribution are numerically
simulated. The calculated results are in fair agreement with the field data.
Key words branch river estuary, suspended load, bed-load, velocity field, erosion and
deposition of river bed, mathematical model.
Neural networks for rainfall runoff modeling
Yang Rongfu Ding Jing Liu Guodong
(Sichuan Union university)
Abstract In this paper, two types of
neural networks for rainfall runoff modeling are suggested: real outputs back-feeding to
input-layer network(ROBIN) and additional output neuron back-feeding input layer system
(ADONIS). They are compared with HYMN(a hydrologically based neural network) and TANK(a
lumped conceptual water buckets model). The results show that the proposed network models
can reasonably simulate daily runoff series.
Key words neural network, rainfall-runoff modeling, real back-feeding.
Preliminary
research on the applications of nonlinear finite element
analysis for reinforced concrete bending structures
Li Fenhua Zhang Jingjian
(North China Institute of Water Conservancy and Hydroelectric Power)
Abstract Based on the regression method,
the relationships between nonlinear finite element analysis method and ultimate strength
method for reinforced concrete structure are established. According to these relationships
and the bearing capacity proscribed in the design code of reinforced concrete structure
currently in effect, the criterion of nonlinear finite element analysis method is
proposed. The approach in this paper are helpful to put the nonlinear finite element
analysis of reinforced concrete into real engineering design code.
Key words nonlinear finite element, regression analysis, reinforced concrete, bearing
strength, ultimate strength.