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Back analysis of mechanical parameters of roller compacted concrete dam

Science china(Technological Sciences) 2010年第3期53卷 848-853页

作者： GU ChongShi 1,2,3,LI Bo 1,XU GuangLei 4 &YU Hong 1,2,3 1 State Key Laboratory of Hydrology-Water Resources and Hydraulic engineering,hohai university,nanjing 210098,china 2college of Water Conservancy Hydropower,hohai university,nanjing 210098,china 3National engineering Research Center of Water Resources engineering Safety,Efficient Utilization and nanjing 210098,china 4 nanjing Hydraulic Research Institute,nanjing 210029,china 1. State Key Laboratory of Hydrology-Water Resources and Hydraulic engineering Hohai University Nanjing 210098 China2. College of Water Conservancy Hydropower Hohai University Nanjing 210098 China3. National Engineering Research Center of Water Resources Engineering Safety Efficient Utilization and Nanjing Nanjing 210098 China4. Nanjing Hydraulic Research Institute Nanjing 210029 China

In view of the diversity and complexity of mechanical parameters of roller compacted concrete dam(RCCD),the uniform design method,partial least-squares regression(PLS)and least squares support vector machine(LSSVM)were applied to the back analysis of RCCD with the use of the complex nonlinear relationship between dam mechanical parameters and dam *** the process of back analysis,the initial samples of parameters were designed with uniform design ***,a transversely isotropic model of RCCD was established by *** *** this model,training samples of LSSVM model could be *** then,the complex nonlinear relationship between relative values of hydraulic components of dam displacements and mechanical parameters was ***,actual relative values of dam hydraulic components are isolated from the measured data of dam displacements by using *** inputting the isolated relative values into LSSVM model,the back analysis values of RCCD mechanical parameters can be *** example analysis showed that mechanical parameters obtained by the above-mentioned back analysis method are reasonable,and the back analysis method is feasible.

关键词： roller compacted concrete dam mechanical parameters back analysis

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EFFECTS OF HYDRAULIC AND GEOMETRIC PARAMETERS ON DOWNSTREAM CAVITY LENGTH OF DISCHARGE TUNNEL SERVICE GATE

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Journal of Hydrodynamics 2009年第6期21卷 774-778页

作者： MOHAGHEGH A college of Water Conservancy and Hydropower engineering Hohai University

Aerators on discharge tunnel outlets may be regarded as an effective protection against cavitation erosion. The air entrainment of aerators is governed by a number of independent parameters, including the bottom slope of releasing free-surface flow tunnel downstream of service gate, the end top slope of pressure tunnel, the height of step, and the Froude number at take-off. During eight phases of experiments, the effects of above-mentioned parameters were observed on the cavity length downstream of the fully open operating service gate of a discharge tunnel. The results show that, the bottom slope of releasing free-surface flow tunnel has obvious effect on the cavity length as well as the Froude number at gate take-off. The effect of the step height variations on the cavity length could be considered for higher discharges and steeper tunnel top slope, particularly in higher discharges, resulting in shorter cavity length downstream of service gate.

关键词： cavitation erosion cavity length discharge tunnel service gate

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Identifiability and identification of a Synthesis Load Model

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Science china(Technological Sciences) 2010年第2期53卷 461-468页

作者： JU Ping, JIN YuQing, CHEN Qian, SHAO ZhengYan & MAO Chao college of Electrical engineering, hohai university, nanjing 210098, china 1. college of Electrical engineering Hohai University Nanjing 210098 China

A Synthesis Load Model (SLM) including both the power load and the distribution network has been proposed in the references. The identifiability of SLM is analyzed at first, it is concluded that the model parameters are identifiable if one of the resistance, reactance and the ratio of them is known. The conclusion is validated through a simulation example. A strategy for parameter identification of SLM is proposed with the combination of the component based approach and the measurement based approach. During parameter identification, only the key parameters playing very important roles in the dynamics of the load and the system are estimated, while the other parameters playing limited role are set as the default values. The proposed strategy is verified by the field measurements.

关键词： power systems load modeling power system identification power distribution lines

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AN IMPROVED ALGORITHM FOR DPIV CORRELATION ANALYSIS

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Journal of Hydrodynamics 2007年第1期19卷 62-67页

作者： WU Long-hua college of Water Conservancy and Hydropower engineering Hohai University Nanjing 210098 China

In a Digital Particle Image Velocimetry （DPW） system, the correlation of digital images is normally used to acquire the displacement information of particles and give estimates of the flow field. The accuracy and robustness of the correlation algorithm directly affect the validity of the analysis result. In this article, an improved algorithm for the correlation analysis was proposed which could be used to optimize the selection/determination of the correlation window, analysis area and search path. This algorithm not only reduces largely the amount of calculation, but also improves effectively the accuracy and reliability of the correlation analysis. The algorithm was demonstrated to be accurate and efficient in the measurement of the velocity field in a flocculation pool.

关键词： Digital Particle Image Velocimetry (DPIV),correlation analysis improved algorithm

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CHANGES OF PAN EVAPORATION IN THE UPPER REACH OF THE YANGTZE RIVER

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Journal of Hydrodynamics 2011年第4期23卷 503-509页

作者： RONG Yan-shu WANG Wen JIANG Hai-yan college of Hydrology and Water Resources Hohai University Nanjing 210098 China State Key Laboratory of Hydrology-Water Resources and Hydraulic engineering Hohai University Nanjing 210098 China

The upper reach of the Yangtze River, 4 511 km long from west to east, contains a great amount of water resources of the Yangtze River Basin. This article studies the characteristics of the pan evaporation, the related meteorological variables, and their effects on the pan evaporation, based on the data of the daily pan evaporation （1980-2008） and other meteorological variables （1961-2008）. The results show that the linear trend of the pan evaporation has remarkable regional features, i.e., the decrease trend in the southwest and the increase trend in the northeast of the investigated region, and the Yangtze River is approximately the boundary of these trends. The meteorological variables have different effects on the pan evaporation depending on the fact that they are in the category the thermal variables or the dynamic variables. The thermal meteorological variables （i.e., air temperature, diurnal temperature range, and sunshine duration） have positive partial correlations with the pan evaporation, while the dynamic ones （air pressure, rainfall, and relateive humidity） have negative correlations with the pan evaporation. The correlation of the wind speed remains to be investigated.

关键词： linear time trend meteorological variable pan evaporation partial correlation Yangtze River

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A novel dynamic coherent eddy model and its application to LES of a turbulent jet with free surface

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Science china(Physics,Mechanics & Astronomy) 2010年第9期53卷 1671-1680页

作者： LU Jun,TANG HongWu,WANG LingLing & PENG Feng college of water conservancy of hydro-power engineering,hohai university,nanjing 210098,china 1. college of water conservancy of hydro-power engineering Hohai University Nanjing 210098 China

We has developed a novel dynamic coherent eddy model,in which the coherent structure-Q criterion introduced by Hunt et al(1988)-is taken into account in the subgrid-scale turbulent viscosity based on the eddy viscosity *** proposed method is to combine the resolved-scale velocity-gradient tensor in the classical Smagorinsky model with Q criterion weighted.A kind of dynamic procedure which was averaged in a general process at temporal direction based on the autocorrelations of the characteristic resolved scales of turbulence was taken for the coefficient of subgrid *** model is implemented in the σ-coordinate and the filtered Navier-Stokes equations are solved by the operator splitting *** validation was explored to 2-D turbulent slot jet both in ambient environment and in regular *** prediction of the present model was compared with the experiment data,including the averaged velocity profiles,the velocity fluctuations and the Reynolds *** model performance is shown to be satisfactory.

关键词： LES subgrid-scale modeling σ-coordinate turbulent jet

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Review on hidden trouble detection and health diagnosis of hydraulic concrete structures

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Science china(Technological Sciences) 2007年第z1期50卷 34-50页

作者： WU ZhongRu1,2?, LI Ji1, GU ChongShi1,2 & SU HuaiZhi1,2 1 college of Water Conservancy and Hydropower engineering, hohai university, nanjing 210098, china 2 National engineering Research Center of Water Resources Efficient Utilization and engineering Safety, nanjing 210098, china college of Water Conservancy and Hydropower engineering Hohai University Nanjing 210098 China National engineering Research Center of Water Resources Efficient Utilization and engineering Safety Nanjing 210098 China

A large number of hydraulic concrete structures have hidden defects such as cracks, erosion, freeze and thaw, thermal fatigue, carbonization. These hidden defects seriously affect the strength, stability and durability of structures. These problems are studied mainly by single monitoring or diagnosis methods at present. The integration of multiple monitoring and diagnosis methods is not applied widely. Besides, the analysis theory on these problems is not developed very well. The systemic study on the aging mechanism of hydraulic concrete structures, time- variation model and health diagnosis is still not enough. The support for engineering practice is limited. Aimed at these major scientific and technological problems and combined with specific projects, study on detection of hidden defects and health diagnosis of hydraulic concrete structure has been carried out. This study includes the following content: field non-destructive examination of hidden defects of hydraulic concrete structures, seepage detection, the construction of in-situ sensing system, the combination of field detection and in-situ monitoring, the mechanism of crack, freeze and thaw, erosion and carbonization of hydraulic concrete structure, mechanism of combination aging; time-variation model of hydraulic concrete structure, theories and methods for health diagnosis of hydraulic concrete structures.

关键词： hydraulic concrete structure hidden trouble detection health diagnosis

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NUMERICAL MODELING PURIFICATION PERFORMANCE OF POT TEST

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Journal of Hydrodynamics 2010年第5期22卷 709-718页

作者： DAI Yu WANG De-guan ZHANG Jin-feng LUAN Qing-hua Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education Hohai University Nanjing 210098 China college of Mechanics and Materials Science Hohai University Nanjing 210098 China college of environmental Hohai University Nanjing 210098 China college of Water Conservancy and Hydropower Hebei University of Engineering Handan 056021 China

A three-dimensional mathematical model was developed to simulate the pollutant removal efficiency of the soil and plants in the pot test. The advection, dispersion, diffusion, adsorption, biochemical reaction and plant uptake processes were taken into account in the model. The three-dimensional modified Richards equation was used in simulating flow field. The mass balance law was employed in deriving the equation for pollutant transport, where the diffusion and dispersion were described with the Fick-type law, the adsorption was macroscopically expressed as form isotherm, and the bio-chemical degradation process was assumed to follow the Monod kinetics. The mathematical model was descretized by the finite element numerical method. In the pot test, the hydraulic loading was assumed to have the intermittent pattern simulating the rainfall duration and the occurrence of frequency, and the concentrations of pollutants in the influent and effluent were measured. The computed overall removal rates for the CODCr and TN in four cases are in the range of 90.62% - 95.43% and 85.01% - 96.46%, respectively. The differences between the computed and tested overall removal rates for the CODCr and TN are smaller than 5%. The time-varying oscillation pattern of the concentrations of the CODCr and TN were rationally simulated, which showed that the model presented in this article could be used to assess the pollutant removal efficiency of the soil and plants in related cases.

关键词： pot test numerical modelling pollutant removal efficiency experiments

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STRUCTURES OF CONFINED VORTEX BREAKDOWN IN CONSTANT DIAMETER PIPE FLOW

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Journal of Hydrodynamics 2009年第3期21卷 341-346页

作者： WANG Ze CHEN Shan-qun college of environmental Science and engineering Hohai University Nanjing 210098 China MOE Key Laboratory for Integrated Regulation and Resources Exploration on Shallow Lake Nanjing 210098China

Numerical solutions of three-dimensional, incompressible and unsteady Navier-Stokes equations for constant diameter swirling pipe flows are used to study vortex breakdown, including the detailed flow structures in the bubble domain and the ＂tail＂ behind the bubble during the vortex breakdown, and a comparison is made between the numerical solutions and the experimental results.

关键词： vortex breakdown confined swirling flow numerical simulation

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A new method of estimating the equivalent elastic modulus of RCCD

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Science china(Technological Sciences) 2007年第z1期50卷 136-143页

作者： GU ChongShi1,2?, WU Yuan1, SU HuaiZhi1,2 & TANG LiHui1 1 college of Water Conservancy and Hydropower engineering, hohai university, nanjing 210098, china 2 National engineering Research Center of Water Resources Efficient Utilization and engineering Safety, nanjing 210098, china college of Water Conservancy and Hydropower engineering Hohai University Nanjing 210098 China National engineering Research Center of Water Resources Efficient Utilization and engineering Safety Nanjing 210098 China

Based on the composite material mechanic theory, the analysis method for the equivalent elastic moduli which are parallel and vertical to the construction interface of RCCD is studied in this paper. The differences between the equivalent elastic moduli which are vertical to the construction interface of RCCD gotten from different methods are discussed in detail. The variation range of the equivalent elastic modulus which is vertical to the construction interface of RCCD is studied based on the principle of minimum complementary energy and the principle of minimum potential energy. The effect of the related influential factors on the equivalent elastic modulus is analyzed. The estimation formula of the equivalent modulus which is vertical to the construction interface of RCCD is proposed. The feasibility of the approach proposed in this paper is analyzed through an example.

关键词： RCCD equivalent elastic modulus variation range estimation method

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