检索结果-南通市图书馆

NUMERICAL SIMULATION OF SCOURING PROCESS UNDER SPILLWAY

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2001年第4期13卷 55-59页

作者： Yang Jian-ming, Wu Jian-hua nanjing hydraulic research institute, nanjing 2.002., china nanjing hydraulic Res. Inst. Nanjing 210029 China

The scour problem under spillway has received a lot of attention in the past decades. For such a complicated problem, most numerical modeling presented only dealt with the water flows in equilibrium scour pools without considering the changing topography of the riverbed. In this paper, the dynamic process is handled with moving grids, and the governing equations are solved using finite volume method with colocated variable arrangement on boundary-fitted non-orthogonal grids. The results show that the given method is efficient, with which the variation of flow parameters, such as mean velocity and mean pressure, etc., can be computed correctly.

关键词： scour pool numerical simulation space conservation law moving grids

STUDIES ON GREY MODEL DYNAMIC PREDICTION TO CAVITATION DAMAGE OF TURBINES

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2003年第5期15卷 29-34页

作者： Wu Fu sheng, Tong Zhong shan, Li Yun hui nanjing hydraulic research institute, nanjing 2.002., china nanjing hydraulic Res. Inst. Nanjing 210029 China

In thus paper, cavitation damage of turbines is firstly analyzed andpredicated from the view point of system engineering by use of the grey system theory. A detaileddescription of modeling, dynamic prediction and accuracy test for the grey system of turbines wasgiven. Two special cases for grey dynamic prediction as well as its accuracy test were *** results fall into the grade I, the accuracy is satisfactory and its prediction requirements canbe met well. It shows that the grey system theory can be employed to predict the cavitation damageof turbines, and it can provide a scientific basis for timely investigation and maintenance ofturbines.

关键词： turbine cavitation damage grey prediction

A DISCUSSION ON CURRENTS AND SUSPENDED LOAD TRANSPORT IN SURF ZONE

在线全文

学校读者我要写书评

暂无评论

china Ocean Engineering 1989年第2期4卷 195-202页

作者： Zhou Jiabao Senior Engineer, nanjing hydraulic research institute, nanjing nanjing hydraulic research Inst. Nanjing China China

In this paper, the distribution characteristics of the breaking wave current and suspended load transport in the surf zone are discussed in main. Based on the measured data of the waves, the form of breaking wave, the breaking wave current and the sediment concentration of suspended load in the offshore surf zone near Nouakchott, the Islamic Republic of Mauritania, the author has analized the law governing the distribution of longshore current and sediment concentration of suspended load by means of statistical method, and presented a calculation method for the longshore sediment transport in offshore surf zone.

关键词： A DISCUSSION ON CURRENTS AND SUSPENDED LOAD TRANSPORT IN SURF ZONE SURF

CHARACTERISTICS OF FLOW RESISTANCE IN OPEN CHANNELS WITH NON-SUBMERGED RIGID VEGETATION

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2008年第2期20卷 239-245页

作者： WU Fu-sheng nanjing hydraulic research institute Nanjing 210029 China State Key Laboratory of Hydrology-Water Resources and hydraulic Engineering Nanjing 210029 China

The flow resistance factors of non-submerged rigid vegetation in open channels were analyzed. The formulas of drag coefficient CD and equivalent Manning＇s roughness coefficient na were derived by analyzing the force of the flow of non-submerged rigid vegetation in open channel. The flow characteristics and mechanism of non-submerged rigid vegetation in open channel were studied through flume experiments.

关键词： characteristics of flow resistance non-submerged rigid vegetation drag coefficient equivalent Manning's roughness coefficient

RECIRCULATING FLOW IN SHALLOW OPEN CHANNEL via THE RNG κ-ε MODEL

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 1999年第1期11卷 41-49页

作者： Kuang Cui-ping (Department of River & Harbour Engineering, nanjing hydraulic research institute, nanjing 2.002., P. R. china ) nanjing hydraulic research Inst Nanjing China

The steady recirculating flow behind a sudden expansion in a shallow channel is studied using the renormalization group (RNG) κ-ε model. The predicted recirculating flow and the reattachment length of the recirculating flow are well-supported by the reported experimental data. The computed effective viscosity, turbulence kinetic energy and its dissipation rate given by the RNG κ-ε model are smaller than that by the standard κ-ε model, while the reattachment length of the recirculating flow is larger. The RNG κ-ε medel overcomes the shortcoming of underpredicting the length of the recirculation zone by the standard κ-ε model.

关键词： open channel RNG κ-ε recirculating flow

Determination of photochemically-generated reactive oxygen species in natural water

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2009年第3期21卷 303-306页

作者： ZHAN Manjun nanjing research institute of Environmental Protection,nanjing 210013,china. nanjing research institute of Environmental Protection Nanjing 210013 China

Reactive oxygen species （ROS） can be produced by interactions between sunlight and light-absorbing substances in natural water environment. ROS may participate in the indirect photolysis of trace organic pollutants, therefore resulting in changes in their environmental fates and ecological risks in natural water systems. Bisphenol A （BPA）, an endocrine-disrupting chemical, exits widely in natural waters. The photodegradation of BPA promoted by ROS （-OH, 1O2, HO2./O2^-）, which were produced on the excitation of ubiquitous constituents （such as nitrate ion, humic substances and Fe（Ⅲ）-oxalate complexes） in natural water under simulated solar radiation was investigated. Both molecular probe method and electron spin resonance （ESR） test were used for the characterization of the generated ROS. It was found that .OH was photochemically produced in the presence of nitrate ions, humic substances and Fe（Ⅲ）-oxalate complexes and that 102 was produced with the presence of humic substances. The steady-state concentrations of .OH was 1.27×10^-14 mol/L in a nitrate solution, and the second-order rate constant of BPA with ＂OH was 1.01×10^10 L/（mol.s）.

关键词： reactive oxygen species Bisphenol A hydroxyl radicals singlet oxygen superoxide anion radical photodegradation

Numerical application of k-ε turbulence model to the flow over a backward-facing step

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2010年第10期53卷 2817-2825页

作者： DING DaoYang1 & WU ShiQiang1,2 1 nanjing hydraulic research institute, nanjing 2.002., china 2 State Key Laboratory of Hydrology-Water Resources and hydraulic Engineering, nanjing hydraulic research institute, nanjing 2.002., china nanjing hydraulic research institute Nanjing China State Key Laboratory of Hydrology-Water Resources and hydraulic Engineering Nanjing Hydraulic Research Institute Nanjing China

A model that uses the operator splitting technique based on Eulerian-Lagrangian method and embeds the k-ε turbulence mode is developed. The model is used to simulate a two dimensional flow over a backward-facing step with triangular mesh discrete flow field. The convection operator is solved with the characteristic method and the diffusion operator and pressure-Poisson equation are solved by finite element method. The results from the example showed that numerical results are well agreed with the experimental data,and that the method can be adapted to simulate complex turbulent flow with strong non-linear convection. The treatment of boundary conditions is also studied in the paper.

关键词： turbulence model the flow over a backward-facing step numerical method

Experimental Study on Superficial Sliding of a New Type of Offshore Platform

在线全文

学校读者我要写书评

暂无评论

china Ocean Engineering 1996年第1期11卷 121-128页

作者： Wang Zhaojing Zhang Ling Senior Engineer, Geotechnical Engineering Department, nanjing hydraulic research institute, nanjing 2.002. Engineer, Geotechnical Engineering Department, nanjing hydraulic research institute, nanjing 2.002. Geotechnical Engineering Department Nanjing Hydraulic Research Institute Nanjing 210024

In order to verify the theoretical design and computation of a new type of platform, laboratory model test of the superficial sliding of the platform is carried out. Test results show that the requirement for the stability of the platform can be satisfied, and the API-82 criterion can be met. It is also suggested that, in order to enhance the stability of the platform, a buried- pad with porous holes and a long apron-board should be adopted in the design of the new type of platform.

关键词： superficial sliding model test offshore platform

Activation of fly ashes by the high temperature and high alkalinity in ASR tests

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2011年第S1期54卷 28-32页

作者： CAI YueBo ,DING JianTong & BAI Yin State Key Laboratory of Hydrology-Water Resources and hydraulic Engineering,nanjing hydraulic research institute,nanjing 2.002.,china State Key Laboratory of Hydrology-Water Resources and hydraulic Engineering Nanjing Hydraulic Research Institute Nanjing China

High temperature and high alkalinity are typical testing conditions to accelerate the appraisal process of the suppressing effect of fly ashes on alkali silica reaction(ASR),but the reaction mechanism of fly ashes would be quite different under such conditions compared to the normal condition of temperature and *** make a reasonable analysis of the suppressing effect of fly ashes,13 types of fly ashes were tested in this paper by both the accelerated mortar bar test method and the 60°C accelerated concrete prism test *** results showed that the effect of fly ashes would be magnified under the condition of high temperature and high *** XRD analysis showed that all the phases of fly ash could react with the hot alkaline solution except for mullite and a small amount of *** ash could be significantly activated by the 80°C 1 mol/L NaOH solution,and form mainly C-S-H phase and P type zeolite,but its effect on inhibiting ASR was exaggerated *** to the mortar strength test and the ASR suppressing test results,C-S-H phase contributed to mortar strength,but its amount did not decide the ASR suppressing effect of fly ash.

关键词： fly ash Alkali silica reaction Activation