Ji Zuwen Hu Chunhong
(China Institute of Water Resources and Hydropower Research)
Abstract In this paper,some
characteristics of flow movement and sediment transport are analyzed by using the flume
experiment data.The cross section of compound channel can be divided into four regions:the
undisturbed region in main channel,the interactive region between channel and plain,the
undisturbed region in flood plain and the boundary region.In the undisturbed regions,the
distribution of longitudinal velocity along the depth has the feature of
lograithmic.Whereas,in the interactive region,the longitudinal velocity does not obey the
logarithmic distribution law,but it can expressed as a revised logarithmic function by
using a wake function.On the basis of the kinematic equation the velocity distribution of
transverse velocity is obtained.In the boundary region,the longitudinal velocity obeys the
law of parabolic distribution.Furthermore,according to the simplified diffusion
equation,the transverse distribution of sediment concentration in the interactive region
is deduced.The analysis is in good agreement with the measured data.
Key words main channel,flood plain,velocity distribution,seidiment concentration.
Abstract Experiment of two-phase mixtures
consisting of neutrally buoyant grains and interstitial liquid are performed on a special
designed rheometer in order to investigate the stress constitutive relation of debris
flow.This rheometer is equipped with an annular cone-plate type shear cell in which
shear-rates can be kept in uniform.Four types of grain and various liquids are used to mix
the test mixtures.The shear stress and normal pressure are measured simultaneoursly.The
results show that ,the granular stress occurred during shearing is not only caused by
collision but also by supporting and friction.The ratios of shear stress to normal
pressure are independent of grain concentration and liquid viscosity,roughly approach to a
constant value.When the concentration becomes higher,the yield strenght of mixture becomes
obvious even though the liquid medium of mixture are Newtonian fluids.In the initial part
of flow curves,there exists a special section which has a property other than that of
higher shear-rate region.Sometimes,a negative slope appears in initial section.This
section can not be explained with a single rheological model.These phenomena may be
important in study of debris flow mechanism.
Key words debris flow,two-phase flow,rheology,rheometry.
Abstract One-dimension vertical
temperature model is developed to simulate the temperature-stratified phenomena of Miyun
Reservior.Heat exchange by effective diffusion,inflow,outflow,thermal advection and
interaction between water surface and atmsphere are considered in this model.The
parameters of the model are determined according to the observed data in 1991.The
predicted temparture in 1992 is in accordance with the observed data.
Key words reservior,water temperature model,water quality.
Abstract The cavitation characteristics of
weir gate slots are quite different from that of two dimensional cavity.The flow over a
curved weir not only causes the considerable low pressure at the bottom,but also changes
the cavitation pattern of the gate slot.The vortex is not always limited in the slot as it
is in two dimensional situation,but is frequently pushed out at the bottom,and then turns
around the cant,where the separated flow takes place.At the intersection of the vortex,the
curved weir and the region of separation,the pressure drops down sharply,which accounts
for the vulnerability to cavitation damage of this area.The incipient cavitation numbers
of weir gate slots are much higher than those of two dimensional cavitation
Key words weir gate slot,hydraulics,cavitation.
Luo Ming |
Yang Yongsheng |
(Sichuan Union University) |
(Tsinghua University) |
Abstract Based on the
experimental results in model test, the modified formula for calculating the take off
angle of jet flow from aerator has been established. The comparison shows that the
calculation results agree with the observed data fairly.
Key words aerator, take off angle, correction coefficient.
Ji Qingfeng Zheng Bangmin
(Wuhan University of Hydraulic and Electric Engineering)
Abstract In this paper the sluice
and spillway flow is solved by using the Monte Carlo method with irregular random walking
grids.New iteration way for free surface and discharge is presented on the basis of the
characteristics of Monte Carlo method.Test calculation shows that the numerical method is
successful and the computational results are in agreement with the experimental data.
Key words sluice and spillway flow, Monte Carlo method,free surface,numerical computation.
Vectorial bedload formula and its application
Shi Bing Liu Xinnian Cao Shuyou
(Sichuan Union University)
Abstract Based on the analysis
and research of Parker vectorial bedload formula, a kind of general vectorial bedload
transport formula is deduced by adding lift force and taking non-equilibrium forces acting
on sediment particle into account. The calculated result of the simplified formula is
compared with the experimental data as well as from Ikeda and the authors. It is shown
that the calculated results agree well with the observed data.
Key words sediment transport, vectorial equations, width adjustment of river.
Rheological
model and three dimensional elasto-viscoplastic finite element
analysis of jointed rock masses reinforced by bolts
Chen Shenghong
(Wuhan University of Hydraulic and Electric Engineering)
P.Egger
(Swiss federal Institute of Technology, Switzerland)
Xiong Wenlin
(Wuhan University of Hydraulic and Electric Engineering)
Abstract In this paper, a new
rheological model of jointed rock mass reinforced by passive, fully-grouted bolt has been
proposed. The model pays special attention to the bolt' s behavior on joints. Based on the model, the
elasto-viscoplastic constitutive equation is established in a 3-D FEM program。 The model has been verified by
the laboratory test and has been applied to the study of the upper gate bay of a
navigation lock.
Key words bolt, joint, rock mass, rheology, FEM.
Investigation
on application of sudden change theory to the analysis
on stability of dam and rock foundation
Gu Chongshi Wu Zhongru Xu Zhiying
(Hohai University)
Abstract In this paper, the basic
principle of the stability of dam and rock foundation is studied by using sudden change
theory. The criterion and calculation model for analyzing stability condition of dam are
put forward by using the point sudden change model. It is shown by example that the
analysis is in accordance with the results of finite element method and model test.
Key words Sudden change theory, dam and rock foundation， stability, criterion.
A numerical method
for post-liquefaction diffusion of liquefied
zone in loose sand
Zhu Jungao Yu Jongqi Jiang Pu
(Hohai University)
Abstract A numerical method is
presented to investigate the post-liquefaction diffusion of liquefied zone in soil due to
the steady state strength. As an example, the diffusion of liquefied zone in an earth dam
body and its foundation is analyzed by using the proposed method. On this basis, the
diffusion of liquefied zone in soils after earthquake and the stability of embankment as
well as earth dam can be further studied.
Key words liquefaction, softening, loose sand, finite element, earthquake, steady state.
The simulation of
complex infinite media and the approximation
of base impedance
Chen Jianyun Lin Gao
(Dalian University of Technology)
Abstract In this paper, an
approximate dynamic substructure approach incorporated with the applying of the dynamic
infinite element developed in Ref.［2］ is proposed to evaluate the dynamic impedance of arch dam
canyon cut. The numerical results show that the combination of this approximate method and
the dynamic infinite element can effectively model the complexity of geometry and
properties of the dam canyon field, whereas efficiency and accuracy of computation are
good.
Key words dynamic infinite element, substructure method, dynamic impedance.
Application of physical
conceptual model in evaluating the
benefits of water and soil conservation
Tang Liqun Chen Guoxiang
(Hohai University)
Abstract The physical conceptual model of
water and sediment yield and the calculation method of the benefits of water and soil
conservation are introduced. The application of this model to calculating the benefits of
water and sediment reduction and analyzing the reason of the water and sediment change are
emphasized in this paper. The results show that, this method is reasonable and feasible.
Key words evaluation, benefits, water and soil conservation, physical conceptual model.
Centrifugal test
study on the behavior of soft clay at sea bottom
under the action of wave force
Yan Shuwang Qu Changlin(Tianjin University)
Sun Baocang(Bohai Oil Corporation)
Zhang Weimin(Naning Hydraulic Research Institute)
Abstract The behavior of the soft
clay under the action of wave forces was studied in centrifugal tests.The soil profile and
the wave characteristics were simulated in the model cell according ot the conditions of
the oil fields in Bohai Gulf. Test results show that the soft clay layer will be seriously
softened near the surface under the maximum height wave action. Whereas, the effect in the
deeper layer was slight. No liquefaction was happened in the silty sand sublayer during
tests. It is proved that the centrifugal test is a valid technique for study of the
interaction between soil and wave.
Key words wave force, soft clay, softened, centrifugal, model test.
Two-dimensional numerical modelling for branching river
Yang Jurui Liu AiyunAbstract According to freeboard surface
arisen from differences of branching river current,the water level of the intake and
outtake section can be adjusted.Based on this principle a numerical modeling of velocity
field and concentration field for natural river with branching is established.Some
important conclusions are obtained from the results of calculation.
Key words branching river,numerical model,velocity field,concentration field.
Rational irrigation quota under limited water supply
Liu Wenzhao
(Institute of Soil and Water Conservation, Chinese Academy of Sciences and MWR)
Abstract This paper reveals that
the constant term in the relationship between crop yield and irrigation quota Y=f(M) has a
decisive effect on the rational irrigation quota under limited water supply. Taking the
overall crop yields or overall net profits on the whole planned area to be maximum as the
targets respectively, the paper gives calculating formulae of rational irrigation quota in
accordance with that the constant term of Y=f(M) is smaller or greater than zero and the
water use coefficient of irrigation water varies with irrigated area or not, supposing one
crop is planted and soil fertility and other conditions are at the same levels in the
whole planned area.
Key words irrigation quota, water-saving irrigation, crop water production function.
