NUMERICAL ANALYSIS OF SIDE DISCHARGES INTO A CHANNEL FLOW USING AN RNG k~(-ε)MODEL

１．　ＩＮＴＲＯＤＵＣＴＩＯＮＳｉｄｅｄｉｓｃｈａｒｇｅｓｉｎｔｏａｃｒｏｓｓｃｈａｎｎｅｌｆｌｏｗｈａｖｅａｗｉｄｅｒａｎｇｅｏｆａｐｐｌｉｃａｔｉｏｎｓｉｎｅｎｖｉｒｏｎｍｅｎｔａｌａｎｄｈｙｄｒａｕｌｉｃｅｎｇｉｎｅｅｒｉｎｇ．Ａｔｙｐｉｃａｌｅｘａｍｐｌｅｉｓｔｈｅｄｉｓｃｈａｒｇｅｏｆｃｏｏｌｉｎｇｗａｔｅｒｆｒｏｍａｐｏｗｅｒｐｌａｎｔｉｎｔｏｔｈｅｒｉｖｅｒ．Ｔｈｅｐｒｅｄｉｃｔｉｏｎｏｆｔｅｍｐｅｒａｔｕｒｅｃｈａｎｇｅｄｕｅｔｏｔｈｅｄｉｓｃｈａｒｇｅｉｓｏｆｇｒｅａｔｉｍｐ…     

THE NUMERICAL COMPUTATION OF TURBULENT FLOW IN TEE-JUNCTION

A numerical model for calculating the turbulent flow in tee-junction is given in thispaper.The calculations are performed using a finite-difference procedure,and turbulence is ac-counted for by using a two-equation k-ε model of turbulence.Results,consisting of mean veloci-ty profiles and pressure losses due to the junction,have been obtained,and show that the flowsituation in tee-junction is very complex.The computed results agree closely with the experimen-tal data and validate that the present model is reasonable and the numerical calculations are suc-cessful.     

NUMERICAL MODELLING OF FLOW FIELD IN A TIDAL RIVER AND THE NEAR FIELD OF INTAKE FOR A NUCLEAR POWER PLANT

This Paper concerns with the numerical modelling of flow field in a tidal river and in the vicinity ofintake of a nuclear power plant. The hybrid method of fractional steps presented in [1] was adopted in thismodelling. In order to simulate the local flow field nearby the water intake meticulously, the technique ofthe match of the coarse and fine grids was used. The numerical results are in good agreement with thein-situ measurements of the main current. The detailed data of local flow field nearby the intake providesthe assessment of the sediment transport characteristics in the vicinity of intake of the nuclear powerplant.     

NUMERICAL SIMULATION AND EXPERIMENTAL STUDY OF THE FLOW FIELD AROUND A CIRCULAR CYLINDRICAL ARTIFICIAL ISLAND UNDER THE ACTION OF WAVES AND VISCOUS CURRENT

ＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＡＮＤＥＸＰＥＲＩＭＥＮＴＡＬＳＴＵＤＹＯＦＴＨＥＦＬＯＷＦＩＥＬＤＡＲＯＵＮＤＡＣＩＲＣＵＬＡＲＣＹＬＩＮＤＲＩＣＡＬＡＲＴＩＦＩＣＩＡＬＩＳＬＡＮＤＵＮＤＥＲＴＨＥＡＣＴＩＯＮＯＦＷＡＶＥＳＡＮＤＶＩＳＣＯＵ...     

NUMERICAL SIMULATION AND EXPERIMENTAL INVESTIGATION OF THE GUIDE-VANE FLOW AND THE INFLUENCE FROM THE LEAKAGE FLOW

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＩｔｉｓｗｅｌｌｋｎｏｗｎｔｈａｔｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｈｙ ｄｒａｕｌｉｃｔｕｒｂｉｎｅｉｓｆｏｒｔｈｅｂｅｓｔｈｙｄｒａｕｌｉｃｅｆｆｉｃｉｅｎｃｙａｎｄｓｔａｂｉｌｉｔｙｉｎｏｐｅｒａｔｉｏｎ .Ｔｈｅｓｔａｂｉｌｉｔｙｏｆｈｙ ｄｒａｕｌｉｃｔｕｒｂｉｎｅａｎｄｉｔｓ ｐｅｒｆｏｒｍａｎｃｅｏｆｃａｖｉｔａｔｉｏｎｅｒｏｓｉｏｎａｒｅｃｌｏｓｅｌｙｒｅｌａｔｅｄｔｏｔｈｅｆｌｕｉｄｆｌｏｗｉｎｔｕｒ ｂｉｎｅｃａｓｉｎｇ ,ｓｔａｙｖａｎｅａｎｄｇｕｉｄｅ…     

THE TURBULENCE CHARACTERISITICS OF OPEN CHANNEL FLOW

ＴＨＥ　ＴＵＲＢＵＬＥＮＣＥ　ＣＨＡＲＡＣＴＥＲＩＳＩＴＩＣＳ　ＯＦ　ＯＰＥＮ　ＣＨＡＮＮＥＬ　ＦＬＯＷＴＨＥＴＵＲＢＵＬＥＮＣＥＣＨＡＲＡＣＴＥＲＩＳＩＴＩＣＳＯＦＯＰＥＮＣＨＡＮＮＥＬＦＬＯＷ￥ＷａｎｇＸｉｎｇ－ｋｕｉ（Ｄｅｐａｒｔ．ｏｆＨｙｄｒ...     

AN EXPERIMENTAL AND NUMERICAL INVESTIGATION OF THE STARTING FLOW OF A UNIFORMLY ACCELERATING CIRCULAR CYLIINDER

The starting flow around a uniformly accelerated circular cylinder is investigatedby flow visualization techncque and solving N-S equations numerically in detail.The results ofthe starting flow are similar with those of the impulsively started one.At lower Re_α,numbers the“phenomenon a”is revealed;the“phenomenon β”appears at higher Re_α numbers,but withonly one secondary vortex.At the early stage of the starting vortex formation,the flow islaminar;at the later stage,the flow transforms into turbulent flow.The velocity distribution inthe flow field is measured with the multiwires installment.The calculational results are comparedwith the results of experiment,and both are in agreement with each other.     

FLOW FIELD CHARACTERISTICS OF THE SAND FUNNEL AND ITS MECHANICS OF SEDIMENT TRANSPORT

The flow in funnel chamber is typical three-di-mensional flow. The experimental results of clear water flowfield and muddy water flow field show that the flow character-istics in the funnel chamber are favorable to the separation ofwater and sand. Tangential velocity sustains the vortexstrength of the funnel chamber, axial velocity is benefit to thesediment sinking, and radial velocity is benefit to sedimentmoving to desilting hole. So the sand funnel is successful insediment disposal. The sand funnel projection has also gooddesilting effectiveness in practice. Its average flushing dis-charge is 3% of inlet canal discharge, the sand disposal rate is100% for the sand with grain diameter of more than 0. 5mm,and is more than 90% for the sand with grain diameter of lessthan 0. 5mm.     

COMPUTATION OF STEADY FLOW BY UNSTEADY FLOW APPROACH AND STEADY FLOW APPROACH

Steady water surface profile of gradually varied flow can be calculated using ei-ther a steady flow approach or an unsteady flow approach. The steady flow approach requires it-erative procedures which may have convergence problems unless the step size 1x is less than amaximum value △x. The unsteady flow approach based on the explicit characteristic method hasa stability problem unless △x is less than △x. A series of numerical experiments were carried outand the results of two approaches are compared.     

THE NUMERICAL SIMULATION OF TWO-DIMENSIONAL OPEN CHANNEL TURBULENCE

A numerical simulation on 2-D open channel turbulence using the two-equationturbulent model(k-e model) is made.The diseretization equations of depth-averaged 2-D differ-ential equation are obtained by the control-volume formulation.Some examples including theflows in straight open channel,symmetry sudden expansion and one-side sudden expansion arecalculated by using the SIMPLE algorithm.The distributions of the flow velocity u,the kineticturbulent energy k,and the turbulent viscosity μ,etc.are obtained.The numerical calculationsindicate a good agreement with experimental data and other turbulent models calulations.     

NUMERICAL SIMULATION OF SKIMMING FLOW OVER MILD STEPPED CHANNEL

1. INTRODUCTION The stepped channel/spillway finds its extensiveapplications in hydraulic and environmentalengineering, which is used to dissipate the energy ofreleased flood and also to be a landscape structure.Flow over the stepped channel/spillway is a…     

COUPLING COMPUTATION OF THE FLOW FIELD AND THE LARGE DEFORMATION OF MEMBRANE STRUCTURE OF STRATOSPHERE AIRSHIPS

In this article, the mathematical model of the coupling of the three-dimensional fluid flow and the large deformation of membrane structure is established. The fluid-structure coupling interaction is simulated using the computational codes developed by the authors. By analyzing the interactions of membrane and flow field, the aeroelasticity of the airship is detailed. All the results are adopted in the focused study of the stratosphere airship in trimmed state.     

SILCO5静止励磁系统灭磁回路的计算和分析

0 引言SILCO5微机静止自并励励磁系统是GE公司比较成熟、可靠性高的定型产品,GE公司将其作为巨型发电机的最理想的配套励磁系统.其主要功能有:最大励磁限制、最小励磁限制、电力系统稳定器、转子过电压保护、发电机转子I2T保护、电压互感器断线保护等.由于其运行可靠、性能优良、功能齐备,国内已有二滩、隔河岩、刘家峡等巨型水电站选用该系统.随着GE公司被三峡工程中标,SILCO5微机静止自并励励磁系统将可能和GE公司的巨型发电机配套,出现在世界上最大的水电站中.但我们通过计算和分析发现,其灭磁回路的设计有较大缺陷.本文以二滩设备为例对此加以分析.     

FLUID-STRUCTURE INTERACTION OF HYDRODYNAMIC DAMPER DURING THE RUSH INTO THE WATER CHANNEL

The hydrodynamic damper is a device to decrease the motion of armament carrier by use of the water resistance. When hydrodynamic damper rushes into the water channel with high velocity, it is a complicated flow phenomenon with fluid-structure interaction, free surface and moving interface. Numerical simulation using the Smoothed Particle Hydrodynamics （SPH） method coupled with the Finite Element （FE） method was successfully conducted to predict the dynamic characteristics of hydrodynamic damper. The water resistance, the pressure in the interface and the stress of structure were investigated, and the relationship among the peak of water resistance, initial velocity and actual draught was also discussed. The empirical formula was put forward to predict the water resistance. And it is found that the resistance coefficient is commonly in the range of 0.3 ≤ C ≤ 0.5, when the initial velocity is larger than 50 m/s. It can be seen that the SPH method coupled with the FE method has many obvious advantages over other numerical methods for this complicated flow problem with fluid-structure interaction.     

DIRECT NUMERICAL SIMULATION OF TURBULENT HEAT TRANSFER IN A WALL-NORMAL ROTATING CHANNEL FLOW

1. INTRODUCTIONTurbulent flows with heat transfer in rotatingframe exist in a variety of industrial , geophysicaland astrophysical applications . The rotation in-duces additional body forces ,i .e .,centrifugal andCoriolis forces , acting on the turbulent…     

NUMERICAL SIMULATION OF FLOW AND HEAT TRANSFER CHARA-CTERISTICS OUTSIDE A PERIODICALLY VIBRATING TUBE

Fluid flow and heat transfer characteristics outside a vibrating tube were numerically simulated by the dynamic mesh method. The mechanism of heat transfer enhancement via periodic vibration of the tube was explored by using the field synergy principle. It is found that the field synergy angle between fluid velocity vector and temperature gradient vector for a periodically vibrating tube is significantly smaller than that for a stationary tube, and it changes approximately according to the sinusoidal law in a vibration period. The effect of time phase of the vibration on the field synergy angle and convective heat transfer coefficient were also discussed. Results indicate that the vibration can enhance heat transfer and this effect is more remarkable when time phase angle ranges between 50° and 1400 in a half period. Especially when the time phase angle is 90°, the average field synergy angle outside the tube reaches the minimum, which leads to the best heat transfer performance.     

NUMERICAL ANALYSIS OF THE PERFORMANCE OF HORIZONTAL AND WAVY SUBSURFACE FLOW CONSTRUCTED WETLANDS

A three-dimensional numerical model is proposed for modeling the TP transport in the Horizontal Subsurface Flow(HSSF) and Wavy subsurface Flow(WSSF) constructed wetland in this article.Both numerical simulations and physical experiments indicate that the removal efficiency of WSSF is higher than that of HSSF.The difference of performance in removing pollutants,e.g.,Total Phosphorus(TP),between HSSF and WSSF is numerically analyzed from three interactive aspects,that is,the hydraulic behavior,the substrate a...