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HYDRODYNAMIC FORCES FOR OVERTOPPING spillways

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Journal of Hydrodynamics 1993年第2期5卷 19-29页

作者： Ashok K.Chugh U.S.Department of the Interior,Bureau of Reclamation Eugineering and Research,Deuver,Colorado 80225 U.S. Dep of the Interior Denver United States

Expressions are derived for calculating hydrodynamic forces from the unit dis- charge,channel slope,and flow and velocity profiles on an overflow spillway.A sample prob- lem is included to illustrate the use of the id... 详细信息

关键词： hydrodynamic forces spillways embankment dam

Multiphase Flow Simulations through Tarbela Dam spillways and Tunnels

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Journal of Water Resource and Protection 2010年第6期2卷 532-539页

作者： Muhammad Abid Muftooh Ur Rehman Siddiqi 不详

Tarbela dam is one of the largest earth filled dam in the world used for power generation and irrigation purposes. Like all reservoirs the sediments inflow in the Tarbela reservoir has resulted in reduction in water storage capacity and is also causing damage to the tunnels, power generating units and ultimately to the plant equipment. This numerical study was performed to predict the flow patterns and characteristics in Tarbela dam. Tunnel 3 and 4 inlets;originally on the bed level were raised in the 3-D model and meshed. Analysis was performed using multiphase flow (water and air) for maximum inflow in the reservoir, i.e., considering summer season and discharging water through different locations, i.e., tunnels and spillways. Pressure, velocities, flow rate and free surface height results obtained were found in good agreement with the analytical and existing results where available. Results show uneven discharge through each gate due to maximum velocity near exits and overall stagnant phenomena of water within the reservoir. Maximum velocity was observed along the spillways outlet. Strong vortex motion was observed near the spillways outlet and tunnel inlets. New design of Tunnel 3 and 4 were suggested to WAPDA in order to decrease the sediment inflow and improvements in design of the spillways were suggested.

关键词： Tarbela Dam Reservoir Flow Simulation Multiphase Flow spillways Tunnels

HYDRAULIC PERFORMANCES OF SKIMMING FLOW OVER STEPPED SPILLWAY

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Journal of Hydrodynamics 1997年第3期9卷 80-86页

作者： Zhou, Hui Wu, Shiqiang Jiang, Shuhai Nanjing Hydraulic Research Inst Nanjing China

Hydraulic performances of skimming flow over stepped spillway was studied by means of hydraulic model experiments. The stepped spillway is a modification of the WES (Water Experiment Station) standard spillway. The experimental results indicated that the stepped spillway is more effective at dissipating energy, the dissipation ratio decreases with increasing discharge, and the free surface air entrainment on stepped spillway occurs much more upstream than on smooth spillway.

关键词： Energy dissipation Hydraulic fluids Hydraulic models Hydraulic structures spillways Surface phenomena

INCEPTION OF AIR ENTRAINMENT ON STEEP SLOPE

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Journal of Hydrodynamics 1993年第3期5卷 9-15页

作者： Ning, Lizhong Wang, Changjiang Shaanxi Inst of Mechanical Engineering Xi'an China

Based on the momentum integral equation of boundary layer on the steep slope and the equation of water depth deduced form both the equation of continuity including the effect of the boundary layer and the energy equation outside the boundary layer on the steep slope, and with the aid of the function of velocity profile in the boundary layer, the water depth and boundary layer were numerically computed by Runge-Kutta method. The method determine parameters in the preceding equation were also discussed in detail for the laminar and turbulent flows. The water depth boundary layer and point of inception of air entrainment calculated by above method agree well with the data obtained by prototype.

关键词： Air entrainment Boundary layers spillways

OVERVIEW OF DAM GULLY EROSION RESEARCH

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International Journal of Sediment Research 2005年第3期20卷 105-115页

作者： G. J. HANSON,D. M. TEMPLE,K. M. ROBINSON,K. R. COOK USDA-ARS HERU Stillwater USDA-ARS HERU Stillwater USDA-NRCS ENTSC Greensboro USDA-NRCS State Office Stillwater

Traditionally gully erosion has been identified with the dissection of the landscape in agricultural settings but it is also recognized as a prevalent erosion feature in earthen dam auxiliary spillways and embankments. Flows through earthen spillways and over dam embankments, due to large rainfall events, have the potential to erode and breach the dam or spillway and result in catastrophic releases from the reservoir. The gully erosion process in an earthen spillway or on an embankment can be characterized by stages of initiation, development, and migration of a headcut. A headcut is defined as a near vertical drop at the upstream end of a gully. The rate of headcut migration is important in determining the breach potential of an earthen spillway and dam embankment. A research program is being conducted to examine the gully erosion processes of earthen dam auxiliary spillways and embankments. This paper describes: 1) the unique test facilities constructed to examine the dominant factors affecting the erosion of earthen spillways and embankments; 2) the observations of the erosion processes and results to date; and 3) the predictive relationships that have been developed for dam gully erosion research at the ARS Hydraulic Engineering Research Unit laboratory in Stillwater, OK.

关键词： Dams Erosion spillways Embankments Gullies Headcut Breach

Risk Analysis of Cavitation in Hydraulic Structures

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World Journal of Engineering and Technology 2021年第3期9卷 614-623页

作者： Gabriel Echávez Engineering Faculty National Autonomous University of Mexico Mexico City Mexico

Damages as a result of cavitation are ever existing problems in high-head spillways. This article presents a brief introduction to the problems associated with high-head spillways and describes a procedure that takes into account the flow near the chute surface where the phenomenon occurs, instead of the mean flow. Application of risk analysis methodology presented can be used to estimate whether there is a possibility of cavitation or there is necessity to determine where the first aereator should be located. The advantage of the procedure herein presented takes into consideration an important new variable, such as the surface roughness. In addition, emphasis should be placed first on the need to investigate other high-head dams which climate change may have exposed them to this kind of damages. Second, there is a need to make measurement in prototype. Finally, to underscore the importance of these problems, a comment is made concerning the Oroville Dam contingency in the state of California, (United States).

关键词： Cavitation spillways Damages High Head Risk Analysis Surface Roughness