2-D Bhatnagar Gross Krook numerical model for unsteady open channel flow

DENG Jia quan
(Pearl River Water Resources Commission)

Abstract:According to the Boltzmann equation and basic relationshipbetween the microscopic and macroscopic variables, the Bhatnagar Gross Krook(BGK) equations governing open channel flow are derived and the consistency between the BGK Boltzmann equations and open channel flow equations is verified. The theoretical derivation shows that St. Venant equation is the special case of theBGK model under the local equilibrium state. Based on the BGK Boltzmann equation, a 2-D numerical model for open channel flows, which satisfies the entropy condition, is established by employing the finite volume method. The proposed model is applied to solve typical open channel flow problems. The comparison betweenthe numerical results and the solutions obtained from other models and experimental data show that the BGK model does not need any entropy fixes and it can accurately simulate the open channel problems in which discontinuous flows exist.

Key words:2-D open channel flows；BGK numerical model；BGK Boltzmann equation; entropy principle

Study on nonlinear multiple time scale turbulence model

YUAN Xin ming¹, TANG Jin chun²,MAO Geng hai², WU Suo rong²
(1.Yangzhou University；2.Zhejiang University)

Abstract:Based on the modified nonlinear algebraic stress model forturbulent flow, a closed non linear multiple time scale model is established. The model is applied to simulate the flow in the vicinity of a step. The computed result is in good agreement with experimental data. Furthermore, the validity of the calculated pressure acting on the ceiling and lateral walls of the inlet of a sluice tunnel is also verified by experimental data.

Key words:turbulence model；multiple time scale model; non linear

Interaction model for wave and current

WU Yong sheng¹, LIAN Ji jian², WANG Zhao yin¹, ZHANG Qing he²
(1.Tsinghua University；2.Tianjin University)

Abstract: A numerical model of wave and current combined flow, featuring closure via the k-ε turbulent model, is developed to study the interaction of wave and current. The parameters describing the wave current field generated by the interaction, within and outside of boundary layer, are calculated numerically by solving a set of nonlinear equations. The comparison between calculation and experimental data shows that the model proposed is reasonable and feasible.

Key words: interaction between wave and current; full flow field; numerical model

Investigation on sediment transport in south channel of Yangtze River estuary by means of GIS technology

GONG Cai lan, YUN Cai xing
(East China Normal university)

Abstract: Based on the powerful GIS software including Arcinfo, Arcvew and ENVI, which can be used as data input, image visualization, map analysis and computing and map output, the charts of the south channel of the Yangtze River estuary from 1988 to 2000 are digitalized. The grid maps and digital erosion and deposition variation maps of the riverbed are obtained, the probable locationand depth of the silting are forecasted. The erosion and deposition map shows that the south channel is deposited in recent 12 years, the sediment mainly comesfrom the upstream and enters the south passage.

Key words: GIS; Yangtze River estuary south channel; bedload sediment transport; variation of erosion and deposition

Deformation of sheet plate due to residual settlement of pile net composite foundation

RAO Wei guo¹, JIANG Hui huang², HOU Qing hua²
(1.Northern Jiaotong University;2. China Academy of Railway Science)

Abstract: The construction and working mechanism of pile net composite foundation are presented. Under te action of embankment the net and the cushion of composite foundation are regarded as an integrated structure. The net is simulated by means of a sheet plate. based on the deformation theory of sheet plate and Winkler's elastic foundation model a method for calculating the residual settlement is developed. The deduced formula reflects the effects of load magnitude, rigidity of net and the soil between the piles, the replacement ratio of composite foundation, pile soil stress ratio and etc. An example is given for demonstration.

Key words: pile net composite foundation; embankment; Winkler's model; sheet deformation; residual settlement

Numerical computation and model test on dynamic response of sandy foundation and embankment

SHAO Sheng jun¹, Keisuke Kojima², Takou Fukui²
(1.Xi'an University of Technology; 2.Fukui University)

Abstract: Based on the effective stress response analysis method using Adachhi Oka's cyclic elastic plastic constitutive law with nonlinear hardening, the numerical simulation of saturated sandy foundation and embankment is carried out by means of FEM. The dynamic response under sine wave load with 0.1g and 0.2g acceleration amplitude, including deformation, pore water pressure andacceleration are obtained. It is shown that the numerical calculation results are rational and can be used to predict the liquefaction of saturated sandy foundation.

Key words: saturated sandy foundation; liquefaction; cyclic elastic plastic constitutive; dynamic response; numerical calculation; model test

Fuzzy optimization of multi dimensional multi objective dynamic programming and its application to farm irrigation

CHEN Shou yu¹, MA Jian qin¹, QIU Lin²
(1.Dalian University of Technology; 2.North China Water Conservancy and HydroelectricPower Institute)

Abstract: Based on the fuzzy optimization theory of multi objective dynamic programming proposed by the author,a fuzzy optimizing multi dimensional and multi objective dynamic programming model is developed.The model can be used in multi stage systems which time dimension is involved.In this method the multi objective staged fuzzy optimization theory and multi dimensionaldynamic programming are applied jointly to solve the problems step by step.The application of this method to inadequate irrigation schedule programming is presented.

Key words: multi objective fuzzy optimization; multi dimensional programming; staged fuzzy optimization theory; inadequate irrigation

Application of transfer function model to predict transport of Atrazine in soil

REN Li, MAO Meng
(China Agricultural University)

Abstract: Laboratory experiment was conducted to investigatethe fate and mobility of Atrazine,a commonly used herbicide,in soil.The transfer function model(TFM) was applied to describe the pesticide transport under steady water flow in saturated homogeneous soil.The objective of this study is to quantify the transport processes of Atrazine in sandy loam through TFM and miscible displacement experiment.The model can be used to characterize the Atrazine transport behavior through soil column with a narrow solute pulse input and with adsorption determined by batch technique.The lognormal probability density function(PDF) was used to fit the drainage effluent data of tracer (bromide).The travelingtime pdf of a linearly adsorbed Atrazine was estimated in terms of the pdf of tracer,and the dynamics of concentration and cumulative quantity leached in the soil were predicted.It was shown that the predicted result is reasonable.

Key words: soil; Atrazine; adsorption; transport; leaching; breakthrough curve; transfer function model; prediction

Lattice model for simulating failure process of rock

YANG Qiang, ZHANG Hao, ZHOU Wei yuan
(Tsinghua University)

Abstract: A lattice model is developed to simulate the failure process of heterogeneous brittle materials.It is assumed that a continuum canbe represented at the meso level by a connected lattice of elastic brittle truss of beam elements.The heterogeneity of the material can be implemented following different manners.The process of fracture is simulated by performing a linear elastic analysis of the lattice under loading and removing an element from thelattice that exceeds a certain failure threshold.After removal of an element theanalysis is repeated.With this model,uniaxial tension and four point shear experiments of single edge notched beams are simulated.It is shown that the simulated crack patterns appear quite realistic.

Key words: lattice model; brittle material; heterogeneity; failure; fracture

Application of radar raingauge estimated mean area precipitation to runoff simulation

LIU Xiao yan¹,MAO Jie ta¹,LI Ji ren²,ZHU Yuan jing¹
(1.Peking University;2.China Institute of Water Resources and Hydropower Researcha)

Abstract: The radar is used to combine with raingauge to measure and estimate the mean area precipitation in the Meishan reservoir area.According tothe estimated result the inflow discharge of the reservoir is simulated based on the Topographic based Hydrologic Model(TOPMODEL).The comparison of the simulated inflow with the discharge estimated according to the measurement of raingauge shows that the proposed method possesses better accuracy.

Key words: weather radar;mean area precipitation;rainfall runoff model

Variations of sediment in upper stream of Yangtze River and itstributary

ZHANG Xin bao^1,2,WEN An bang¹
(1.Institute of Mountain Hazard and Environment,CAS；2.Instifute of Earth Enviroment, CAS)

Abstract: The observation data show that the sediment yield of Jialing River has decreased since 1980s,while the sediment yield of Jinsha River has increased.The cause of this change is analyzed.It is shown that the influence of engineering works on increment of river sediment of Jinsha River basin is much greater that in Jialing River basin due to the fact that the Jinsha River basin is characterized by deeply dissected plateau gorge landform and the jailing River basin by gently dissected hill landform.Current decline of sediment yield in the Jialing River is caused by the positive influences of human activities on reduction of sediment,such as revegetation,soil conservation and water conservation works.The increase of sediment yield in Jinsha River is caused by the negative influence of human activities,such as land degradation,engineering works and channeling works.

Key words: current variation; sediment yield; Jinsha River; Jialing River; upper stream; Yangtze River

Back-propagation neural network model for soil moisture forecast of winter wheat field

SHANG Song-hao, MAO Xiao-min, LEI Zhi-dong, YANG Shi-xiu
(Tsinghua University)

Abstrac: Based on the field soil moisture observation data for winter wheat in Yongledian Experimental Station,Beijing,during growing period,a back-propagation(BP) network model for soil moisture forecast is established。The model takes main factors influencing soil moisture regime into account.The network is trained by part of observation data before the application to forecast of soil moisture with different irrigation treatment in two years.The predicted soil moisture fairly well agrees with the observation data.

Key words: winter wheat; soil water storage; soil moisture forecast; back-propagation neural network

Measurement and calculation of air concentration distribution of self aerated flow in spillway tunnel

DENG Jun,XU Wei lin,QU Jin xue,DONG Jian wei
(Sichuan Universtiy)

Abstract: The effect of tunnel ceiling on air concentration distribution is studied experimentally.The measurement shows that air concentration decreases with the increase of elevation in the vicinity of ceiling.Besides,air concentration in water drop zone will be reduced and the maximum air concentration along the vertical line may be lower than 99%.A theoretical formula is establishedfor calculating the air concentration of self aerated flow in spillway tunnel.A simplified formula for air concentration based on reasonable assumption is proposed.The validity of the calculation is verified by experiments.

Key words: self aerated flow;air concentration;spillway tunnel;remaining height

Analysis of rock mass stress states for route selection of water supply works in Shenzhen city

YANG Geng, WU Zhan shou
(Shenzhen Water Resources Planning and Design Institute)

Abstract: The paleotectonic stress field is evaluated and the present stress states of the rock mass in different sections are calculated using plane strain and 3-D numerical simulation according to the measured stress data.The activities of the fault zone are evaluated.The result provides the background information for route selection of the water supply works.

Key words: water supply works; rock mass stress states; route selection

Computer aided management system for surge flow irrigation basedon full hydrodynamic model

XIE Chong bao, XU Di, HUANG Bin, LIU Qun chang
(National Center of Efficient Irrigation Engineering and Technology Research)

Abstract: The computer program based on full hydrodynamic model is developed for surge flow irrigation modeling and design.The system can be used to simulate the surface water movement under intermittent wetting and drainage,to determine a suitablecombination of several design and management variables that characterize the surface surge flow irrigation event and to select an optimal field irrigation scheme with high irrigation performances.The system also has the function managing and providing information related to application of surge flow irrigation technique.

Key words: surge flow irrigation; full hydrodynamic model; irrigation design and management variables; infiltration; simulation

Numerical analysis of pile soil interaction in long piled wharf of Tianjin Port

LIAO Xiong hua¹,ZHANG Ke xu²
(1.Tongji University;2.Harbin University of Technology)

Abstract: Based on the modified FEM for pile soil interaction analysis the numerical simulation of long piled wharf in Tianjin port is carried out.The pile structure is modeled by using the normal beam rod theory and generalized freedom method of nodes around the pile structure.The simple laying contact pattern of the pile top and beam are simulated through the master slave displacement constraint.Furthermore,the stress history of soil mechanics is thoroughly considered in soil constitutive relation.The proposed method reflects the dimensional effect of large diameter pile body and the geometry topology of pile soil interaction.

Key words: pile soil interaction;long piled wharf;port engineering;FEM;numerical analysis

Reliability analysis on strong shear weak bendingdesign of reinforced concrete columns

MA Hong wang
(Tongji University)

Abstract: According to the current code for seismic design, the parameters of reinforced concrete columns are considered as random variables. Failure mode of columns is assumed as series system. On this basis the reliability of strong shear weak bending design is analyzed using Monte Carlo simulation method。The probability of shear failure prior to flexural failure is obtained. It provides the basis for reasonably determining the strengthened shear strength factor.

Key words: reinforced concrete column; strong shear weak dending design; reliability analysis; Monte Carlo simulation

Application of artificial neural network method to analyze the safety factor of rock slope

LU Feng¹, SUN Dong-ya¹;ZHANG Guo ming²
(1.China Institute of Water Resources and Hydropower Research；2.Zhending Water Resources Bureau of Hebei Province)

Abstract: Neural network method is applied to establish the nonlinear mapping relation between the rating factors of Chinese Slope Mass Rating (CSMR) system and slope safety factor. The mapping relation is proved to be accurately reflects the effect of CSMR system factor on slope safety factor.Case study shows that ANN method can be effectively used to calculate the safety fastor of rock slope and achieve reliable analysio results.

Key words: slope; safety factor; Chinese Slope Mass Rating system; artificial neural; mapping relation