Journal of Hydraulic Engineering
1998定 及11豚
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Journal of Hydraulic Engineering 1998定 及11豚 |
Three aspects of morphological
evolution Process
in the Lower Yellow River
Yin Xueliang Chen Jinrong Liu Xia
Abstract It is pointed out that the
morphological evolution process of the lower Yellow River has three elementary
aspects:shallow cross section,mild longitudinal slope and intensive amount of
aggradation.One of the main characteristics of the River is frequently shifting of the
main channel,resulted from more shallow cross section and more steep longitudinal
slope.The other one is severe siltation due to the formation of the sediment transport
capacity related to the geometric features of the longitudinal profile and cross
section.The river's geometry depends on the relationship between sediment and water
transport.The Lower Yellow River belongs to a shallow river with frequently shifting of
the main channel.Siltation along the river has formed the mild riverbed slope thousands of
years ago.The silt transport capacity generated by mild bed slope and shallow cross
section is much smaller than the inflow sediment from the watershed.This is the cause of
consistent serious siltation of the Lower Yellow River.
Key words the Yellow River,shallow cross section,meandering,siltation,flow and sediment
transport.
Study on gas-liquid transient flow
caused by emptying of surge tank
Yang Kailin Dong Xinling
Abstract In this paper the gas-liquid
transient flow caused by emptying of surge tank is studied.The formula for computation of
the air discharge from a surge tank into the down stream pressurized pipeline is
proposed.A new concept of gas particle is introduced to determine the gas distribution in
the pipeline with the help of Lagrange method.The discrete gas-liquid model is used to
calculate the water pressure in the pipeling.The comparison of the calculation result with
test data verifies that the mathematical model developed herein is applicable for
estimating the water pressure in the gas-liquid transient flow.
Key words emptying of surge tank,gas-liquid transient flow,gas particle and discrete
gas-liquid model.
Study on soil infiltration
law with artificial rainfall
and numerical simulation
Feng Shaoyuan(China Agricultural
University)
Ding Yueyuan(Beijing Institute of Hydraulic Research)
Yao Bin(China Irrigation and Drainage Corp.)
Abstract The field experiments of soil
infiltration are conducted under the condition of four treatments with different rain
intensity.The numerical simulation are carried out in the process of filtration and a
simple computational method is given to analyze the course of rainfall,infiltration and
runoff.
Key words artificial rainfall,infiltration,numerical simulation
The mathematical model of water
movement from
a surface trickle source
Li Guangyong Zeng Dechao Zheng
Yaoquan
(China Agricultureal University)
Abstract The mathematical model
of water infiltration from a surface trickle source was established based on the principle
of non-saturated soil moisture movement.Surface moving saturation area is treated
according to the conservation law of mass.The calculated results were verified by
laboratory test.
Key words trickle irrigation, mathematical model, water movement.
Law of similarity for air cushion surge chamber model test
Suo Lisheng Zhang Jian
(Hohai University)
Abstract Similarity law for
hydraulic model test of air cushion surge chamber is studied in this paper.It is suggested
that the chamber may be substituted by an equivalent open surge tank of variable cross
section in hydraulic model test with conventional testing method.The formula for
calculation of the equivalent surge tank is derived and the method for transformation of
measured data is presented.
Key words air cushion surge chamber, surge tank, similarity law, hydraulic model test.
Experimental study on water flow in a centrifugal pump impeller
Li Wenguang
(Gansu University of Technology)
Abstract Water flow in a
centrifugal pump impeller with small blade outlet angle are measured by using 2-D laser
Doppler velocimeter at the best efficiency and part-loading points respectively.The
results show that the wake in the suction side of the blade is narrow and the jet does not
exist in the pressure side,the flow in the impeller does not conform to the well known
jet-wake flow model.
Key words centrifugal pump, impeller, flow.
Study on flow induced vibration of spillway guide wall
Liao Jijian Cui Guangtao Huang
Jinlin
(Tianjing University)
Abstract This paper deals with
the flow induced vibration of guide wall in the Three Gorges Project.The properties of the
amplitude and frequency spectra of fluctuating pressure on guide walls are summarized.The
responses of flow induced vibration of the guide wall are calculated and compared with the
results of the hydroelastic model.The main excitation source is also studied.Finally,the
safety of guide walls suffered from induced vibration is evaluated.
Key words guide wall,fluctuating pressure, flow induced vibration, hydroelastic model.
Investigation
on sediment transport capacity with high concentration
for fluvial river
Fei Xiangjun Shu Anping
(Tsinghua University)
Abstract In this paper, the
typical formulas for sediment transport capacity which have been widely used are reviewed.
Based on flume tests and theoretical anaysis, by establishing the relation between the
complex index Yc and Sv(4R/d90), a new formula for
sediment transport capacity, suitable for sediment laden flow with concentration of more
than 40 kg/m3, is suggested. This formula has been satisfactorily verified by
the measured data from lower reach of the Yellow River, Luohui Channel and other flume
tests.
Key words hypoconcentrated flow, sediment transport capacity, flowing resistance.
Exposition on concentration distribution of suspended sediment along depth
Wang Fuquan Ding Jing Cao Shuyou
Li Houqiang
(Sichuan Union University)
Abstract Research achievements on
concentration distribution of suspended sediment along depth based on diffusion theory,
two-phase flow theory, turbulent burst theory and stochastic theory are summarized. A
simplified formula which is more convenient to application is proposed by the authors.
Analytical formulas for concentration distribution of suspended sediment based on various
theory are deduced.
Key words sediment, vertical distribution, diffusion, turbulence, two-phase flow.
Discussion on hydraulic properties of plane vortex with standing center
Ni Hangen
(Dalian University of Technology)
Chen Xia
(China Institute of Water Resources and Hydropower Research)
Abstract This paper is concerned
with the hydraulic properties of vortex which has a standing center and is enclosed by
stream lines. The parameters such as velocity, pressure, vorticity, circulation and
angular momentum are deduced. Furthermore, four connective conditions are discussion to
connect the vortex to the main flow. The results are applied to some practical conditions
such as post-step flow, hydraulic jump and channel junction. Some of the conclusions are
very useful.
Key words hydraulics, vortex, post-step flow, hydraulic jump, channel junction.
Numerical simulation of sedimentation using turbulent
liquid-solid two-phase flow model
Ni Hoqing
(China Institute of Water Resources and Hydropower Research)
Zhou Lixing Zhou Junyan
(Tsinghua University)
Abstract A quasi-3D model
consisting of depth-averaged 2-D model, based on a two-fluid model of turbulent
liquid-solid flows, is proposed to simulate sedimentation in estuary. Comparison of
predictions with experiments shows that the proposed quasi-3D model is better than the
depth-averaged 2-D model in predicting sediment flows.
Key words sedimentation flow, liquid-solid flows, numerical simulation.
The CAD Software for
linked-tetrashaft
double-cantilever flat flap-gate
Fu Qiang
(North-east Agricultural University)
Abstract The principle for developing the
software is introduced and the mathematical model for the member system of the gate is
established. The software was successfully applied to preliminary design of several
projects.
Key words linked-tetrashaft, double-cantilever, flat flap gate, CAD, software development.
Model test for dam breach of Gouhou concrete face sandy gravel dam
Liu Jie Dind Liuqian Miao
Liangjuan Yang Kaihong
(China Institute of Water Resources and Hydropower Research)
Abstract The cause of the dam breach are
revealed by model test. The following conclusions have been drawn:1. if large amount of
water leakage happened at the joint of concrete face and the bottom of wave wall, the
seepage in dam can only be a vertical seepage so the seepage water cannot be drained out
from downstream slope above EL. 3260; 2. only when the upper part of the concrete face is
separated from the dam body and the separated section reaches EL. 3270, the leakage water
from the joint can flow out at EL. 3260 of the downstream slope; 3. before the breach, the
dam body was not totally saturated; 4. because there is a highly permeable piping layer,
it causes piping and contacting erosion and the drained water will scour the downstream
slope and cause sloughing. Under the action of piping, scouring and sloughing the wave
wall collapsed and at last the breach happened.
Key words leakage of the joint, declutch of the concrete face, piping of the highly
permeable layer, slope scouring, dam breach.
A statistical measure of complexity in hydrological systems
Feng Guozhang Song Songbai
(Northwestern Agriculture University)
Li Peicheng
(Xi'an Institute of Engineering)
Abstract In this paper, the essential
concept on the complexity in hydrological systems and its difference from the complexity
in general physical systems are described. A method to quantify the complexity in
hydrological systems from both the probabilistic macro-hierarchy of accessible states of
the systems and micro-hierarchy inside the states is developed. The complexity in
hydrological systems is quantified by a degree of hydrological complexity as a product of
information entropy and hydrological dis-equilibrium. The degree of the complexity is a
combination of probability, statistics and non-linear theory, and may be adopted as a
statistical measure of the complexity in hydrological systems. The method can be
effectively used to identify the complexity in hydrological systems and to describe
fractal and chaotic features in the systems by traditional probabilistic and statistical
methods due to the connection of the complexity and information dimension.
Key words hydrological system, complexity, statistical measure, degree of dis-equilibrium,
degree of complexity, information entropy, macro-hierarchy, micro-hierarchy.