THEORETICAL AND EXPERIMENTAL STUDIES OF THE FLARING GATE PIER ON THE SURFACE SPILLWAY IN A HIGH-ARCH DAM

The experimental studies of the flaring gate pier applied on the surface spillway in a high-arch dam show that a shock-wave will appear when the pattern of the flow is kept as super-critical. Meanwhile, the water depth at the outlet increases significantly, the flow moves downward in different directions, and the plunging jet is in a narrow and long shape, with a full longitudinal diffusion. In addition, the variation of the flaring gate pier design parameters affects little the discharge capacity of the surface spillway, these parameters including the contraction ratio , the contraction angle and the spillway chute angle . The pressure on the bottom of the spillway increases along the way and reaches the maximum before the outlet, and then decreases rapidly. Due to the flow impacting, the pressure on both sidewalls increases abruptly at the turning line of the flaring gate pier. To see the characteristics of the flow in the flaring gate pier, a simple calculation method is suggested based on the conversation of energy and mass, and the calculation methods for the jet trajectory and the horizontal length in air are also proposed. The results are found in good agreement with experimental data.     

宽尾墩与台阶坝面联合消能工的试验探索

通过对宽尾墩与台阶坝面联合消能工的机理分析,借助工程水力学模型试验,提出一种新型宽尾墩———X型宽尾墩。这种宽尾墩能适应大小流量的变化,具有良好的消能效果,消能率达60%～70%,比常规宽尾墩消能率高5%～10%;产生的射流对消力池底板的最大冲击压力,比常规宽尾墩小30%。因此,X型宽尾墩具有广阔的应用前景。     

RELATIONSHIP OF FIRST STEP HEIGHT, STEP SLOPE AND CAVITY IN X-SHAPED FLARING GATE PIERS

The energy dissipation of X-shaped flaring gate piers ahead of a stepped spillway was adopted in the Suofengying Hydroplant. Under the circumstance that the first step is higher than others, at the step surface an aerated cavity occured behind piers. The interaction of the weir head, the elevation difference between crest and chamber outlet, the first step height, the slopes of weir end and step, and the size of cavity, was investigated, the expression was derived to characterize their relationship, and the corresponding curves were plotted. The comparison of the calculated and simulated results with the measured data was performed. When the slopes of step and weir end are equivalent, the relative height difference between the first and second steps becomes the main factor influencing the aerated cavity. These findings may be useful in practical applications.     

NUMERICAL SIMULATION FOR THE STEPPED SPILLWAY OVERFLOW WITH TURBULENCE MODEL

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｓｔｅｐｐｅｄｓｐｉｌｌｗａｙｈａｄｂｅｅｎｕｓｅｄａｔｔｈｅｂｅｇｉｎｎｉｎｇｏｆｔｗｅｎｔｙｃｅｎｔｕｒｙ[1 ] .Ｉｎ 1 971 ,Ｅｓｓｅｒｙｅｔａｌ.[2 ] ｃｏｎｄｕｃｔｅｄａｍｏｄｅｌｔｅｓｔｆｏｒｔｈｅｄｅｓｉｇｎｏｆ     

THREE-DIMENSIONAL TURBULENCE NUMERICAL SIMULATION OF A STEPPED SPILLWAY OVERFLOW

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅａｐｐｌｉｃａｔｉｏｎｏｆｔｈｅｓｔｅｐｐｅｄｓｐｉｌｌｗａｙｈａｓｈａｄａｌｏｎｇｈｉｓｔｏｒｙ .Ｔｈｅ ｐｈｙｓｉｃａｌｍｏｄｅｌｔｅｓｔｓｔｕｄｙｏｆｔｈｅｓｔｅｐｐｅｄｓｐｉｌｌｗａｙｈａｓｂｅｅｎ ｐｅｒｆｏｒｍ     

THREE-DIMENSIONAL TURBULENCE NUMERICAL SIMULATION OF A STEPPED SPILLWAY OVERFLOW

In this paper, the κ-ε two-equation turbulence model was used to simulate the three-dimensional turbulent flow of the stepped spillway at the Yubeishan reservoir. In order to solve the curved free water surface and to handle the complex boundary conditions, the fractional Volume Of Fluid (VOF) model that is applicable to the solution of the stratified two-phase flow was intorduced to the κ-ε turbulence model and the unstructured grid was used for the discretization of the irregular simulation domain. By these methods, the turbulent flow field of the stepped spillway was simulated successfully.The location of the free surface along the spillway, the magnitude and distribution of the velocity, the pressure distribution on the step surface, the turbulence kinetic energy and turbulence dissipation rate were obtained by simulation. The changes and distributions of these characteristics along the width of the spillway were also obtained. The energy dissipation ratio of the stepped spillway was calculated according to the upstream and downstream water depth and velocities.     

宽尾墩+阶梯溢流坝+消力池的紊流数值模拟

宽尾墩 阶梯溢流坝 消力池一体化的坝面泄流形式是我国科技工作者提出的新型水工设施,已在实际工程中有所应用,但缺少数值计算成果。阐述了针对这种极其复杂的坝面形式进行的数值模拟,计算了设计和正常水位条件下的水力特性和宽尾墩进出口处的紊动能以及耗散率,数值计算结果与试验数据基本吻合。数值计算时单宽过量已达141m3/s·m,对宽尾墩 阶梯溢流坝 消力池一体化的方式有必要进行更深入的研究。     

索风营水电站泄洪消能水力特性试验研究

为缩短工期，提高工效，索风营水电站采用宽尾墩 台阶坝面 消力池的联合泄洪消能形式。通过三种不同比尺的模型试验，分析比较了枢纽布置、表孔泄流能力、宽尾墩、台阶坝面及下游消能防冲等问题，提出了X形宽尾墩，它具有传统宽尾墩大单宽泄洪消能作用，同时又有台阶坝面小流量消能作用，使消力池底板承受冲击压强减小30％。     

NUMERICAL SIMULATION OF WATER QUANTITY AND QUALITY FOR RIVER-TYPE RESERVOIRS

ＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＯＦＷＡＴＥＲＱＵＡＮＴＩＴＹＡＮＤＱＵＡＬＩＴＹＦＯＲＲＩＶＥＲ－ＴＹＰＥＲＥＳＥＲＶＯＩＲＳＷａｎｇＨｕｉ－ｍｉｎ（ＨｏｈａｉＵｎｉｖｅｒｓｉｔｙ，Ｎａｎｊｉｎｇ２１００９８，Ｐ．Ｒ．Ｃｈｉｎａ）（Ｒｅｃｅｉ...     

NUMERICAL SIMULATION OF ATOMIZATION RAINFALL AND THE GENERATED FLOW ON A SLOPE

This article studies the atomization rainfall and the generated flow on a slope by numerical simulations.The atomization rainfall is simulated by a unified model for splash droplets and a suspended mist,and the distribution of the diameter of splash rain drops is analyzed.The slope runoff generated by the atomization rainfall is simulated by a depth-averaged 2-D model,and the localization of the rainfall intensity in space is specially considered.The simulation results show that:(1) the median rain size of the atomization rainfall increases in the longitudinal direction at first,then monotonously decreases,and the maximum value is taken at the longitudinal position not in consistent with the position where the maximum rain intensity is taken.In the lateral direction the median rain size monotonously decreases,(2) since the atomization rainfall is distributed in a strongly localized area,it takes a longer time for its runoff yield to reach a steady state than that in the natural rainfall,the variation ranges of the water depth and the velocity in the longitudinal and lateral directions are larger than those in the natural rainfall.     

NUMERICAL SIMULATION OF TWO-PHASE GRAVITY CURRENTS OVER A POROUS SUBSTRATE

1 .　INTRODUCTIONGravitycurrentsoccurinmanysituationsaris inginbothindustrialandnaturalsettings[1 2 ] .Commonlythecurrentisdrivenbycompositionalortemperaturedifference ,toleadtoahomoge nouscurrent ,orbysuspended particulatematter ,toleadtoaparticle drivencurrent.Combinationsbybothparticleandcompositionalortemperaturedifferencecanalsooccur[3] .Mostoftheresearchesareconcentratedonthesituationswherethecur rentsflowaboveanimpermeableboundary .How evertherearemanyimportantcaseswheregravitycurr…     

THE PREDICTION OF WATER AND SALT REGIME IN SALTAFFECTED AREAS BY NUMERICAL SIMULATION

ＴＨＥＰＲＥＤＩＣＴＩＯＮＯＦＷＡＴＥＲＡＮＤＳＡＬＴＲＥＧＩＭＥＩＮＳＡＬＴＡＦＦＥＣＴＥＤＡＲＥＡＳＢＹＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮ￥ＺｈａｎｇＹｕ－ｆａｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＩｒｒｉｇａｔｉｏｎａｎｄＤｒａｉｎａｇｅ，Ｗｕｈａ...     

NUMERICAL SIMULATION OF 3-D TURBULENT FLOWS OF PLUNGE POOL AND ENERGY DISSIPATION ANALYSIS

A 3-D numerical model for simulating the complicated turbulent flows was developed and the code was made. A numerical calculation of the plunge pool of Laxiwa project in China was carried on. Those 3-D distributions of velocity,pressure on bottom wall,turbulence kinetic energy and turbulence energy dissipation rate are revealed in detail and the detailed flow patterns of plunge pool were shown. By studying on the characteristics of turbulent diffusion and energy dissipation,the calculated results show that the major turbulence and energy dissipation are taken place near the axis of water jet. The calculated results also indicated that the calculated maximum impact pressures on the bottom wall of the plunge pool have a good agreement with those obtained by physical hydraulic model test.     

NUMERICAL SIMULATION ON 2-D WATER-AIR TWO-PHASE FLOW OVER TOP OUTLET

Flood discharge over top outlet of dam is simu-lated by 2-dimension water-air two-phase mathematical model.Distribution of dynamic pressure, turbulent kinetic energy (k), turbulent dissipation rate (ε) , free water surface and veloci-ty field have been obtained. The simulated results were testedby physical model, which shows that the computed results areidentical with that of the physical model.     

NUMERICAL SIMULATION OF 2-D TIDAL FLOW AND WATER QUALITY UNDER THE CURVILINEAR COORDINATES

This paper presents a numerical method to simulate the 2-D tidal flow and water quality under the curvilinear coordinates. In order to overcome the computational difficulties in natural rivers, such as the complicated boundary figures, the great disparity between length and width of computational domain, etc. , boundary-fitted grid is used, the irregular domain in physical plane is transformed into a rectangular domain in transformed plane, and the depth-averaged momentum equations and mass equation are rewritten and discretized based on the finite volume techniques in curvilinear coordinates. Practical application of the method is illustrated by an example for the Dachangzhen Section of the Yangtze River. A fair agreement between the values measured and computed demonstrates the validity of the method developed.     

3-D NUMERICAL SIMULATION OF SPRAY DIFFUSION ON ENVIRONMENT

An equation of atomization quantity from energy dissipation by hydraulic jump was derived from dimensional analysis. Applying the Gauss diffusion equation, the spray diffusion in valley was studied under the conditions of continuous line source and random wind direction. Considering the spray-rain switching process, coagulation, condensation and evaporation of droplets, the authors calculated the air temperature, air relative humidity, spray density and the rainfall intensity in the lower reaches. The 3-D numerical results agree well with portotype monitoring data.     

NUMERICAL SIMULATION AND COMPARISON OF WATER INTAKE-OUTLET METHODS IN POWER PLANTS

The eclipsed form arrangement and march-past method of water intake-outlet arrangements in power plants were researched by 3-D numerical simulation based on the k-ε two-equation turbulence model. Firstly, the flowing characteristics of eclipsed form arrangement were analyzed and the effects of some main factors on inlet temperature were investigated. The simulation results are basically in agreement with those of the previous experiments. Then, by comparing the inlet temperature of the above two intake-outlet methods, the superiority and its existent conditions of the eclipsed form were examined.     

NUMERICAL SIMULATION OF LEVEE BREACH FLOWS UNDER COMPLEX BOUNDARY CONDITIONS

Levee or dam failure can cause a significant disaster in most cases. A good prediction of the flood process especially in a real complex terrain is necessary for working out emergency plans for levee or dam breaches. Numerical simulations of levee or dam breach flow were carried out often with constant flow parameters and in relatively simple channels rather than in natural rivers with complex boundaries. This article presents our dedicated studies on the 2-D numerical model of levee or dam breach hydraulics with finite difference schemes. The good performance of the model is demonstrated by comparisons with the theoretical solution of an idealized dam-break flow over a frictionless flat rectangular channel. The model is also validated through its stability and conservation properties. The model is applied to simulate the flood propagation under complex boundary conditions, and the unsteady flood process in a river and in the dry floodplain with a complex bed terrain simultaneously. Furthermore, with respect to engineering practice, the numerical solutions can give special guidance to the effects of parameters such as the flood depth at different sites and the inundated area at different time periods after the levee breach and the travel time of the flood waves, which may be very important for practicing engineers in an efficient flood management.     

STUDIES ON THE NUMERICAl SIMULATION OF UNSTEADY FLOWS

ＳＴＵＤＩＥＳＯＮＴＨＥＮＵＭＥＲＩＣＡｌＳＩＭＵＬＡＴＩＯＮＯＦＵＮＳＴＥＡＤＹＦＬＯＷＳ￥ＬｕＸｉ－ｙｕｎ（ＵｎｉｖｅｒｓｉｔｙｏｆＳｃｉｅｎｃｅａｎｄＴｅｃｈｎｏｌｏｇｙｏｆＣｈｉｎａ，Ｈｅｆｅｉ２３００２６，Ｐ．Ｒ．Ｃｈｉｎａ）Ｓｕｐｅｒｖｉ...     

NUMERICAL SIMULATION OF 3-D CORNER FLOWS IN A CIRCULATING WATER CHANNEL

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｃｉｒｃｕｌａｔｉｎｇｗａｔｅｒｃｈａｎｎｅｌ (ＣＷＣ)ｈａｓｂｅｅｎｐｌａｙｉｎｇａｎｉｍｐｏｒｔａｎｔｒｏｌｅｉｎｈｙｄｒｏｄｙｎａｍｉｃｅｘｐｅｒｉ ｍｅｎｔｓ,ｓｕｃｈａｓｓｈｉｐｍｏｄｅｌｔｅｓｔｓ,ｏｃｅａｎｅｎｇｉｎｅｅｒｉｎｇ ,ｓｐｏｒｔｓｓｃｉｅｎｃｅｓ,ｅｔｃ .Ｔｏａｃｈｉｅｖｅｈｉｇｈｐｅｒｆｏｒｍａｎｃｅ ,ｉｔｉｓｅｓｓｅｎｔｉａｌｆｏｒａｄｅｓｉｇｎｅｒｔｏｋｎｏｗｔｈｅｄｅｔａｉｌｓｏｆｆｌｏｗｉｎｔｈｅＣＷＣ .Ｂｅｃａｕｓｅｏｆｔｈｅｃ…