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spillway
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Reply to discussions by E.F.R. Bollaert and A.J. Schleiss on "Jet impact geometry and plunge pool dimensions effects on dynamic pressures at pool sidewalls"
, Article Canadian Journal of Civil Engineering ; Volume 35, Issue 11 , 2008 , Pages 1351- ; 03151468 (ISSN) ; Zarnani, P ; Sharif University of Technology
2008
Numerical modeling of flow over a dam spillway
, Article 2006 ASME Joint U.S.- European Fluids Engineering Division Summer Meeting, FEDSM2006, Miami, FL, 17 July 2006 through 20 July 2006 ; Volume 1 SYMPOSIA , 2006 , Pages 343-349 ; 0791847500 (ISBN); 9780791847503 (ISBN) ; Shayanfar, M ; Jabbari, E ; Mohammadi, M. H ; Sharif University of Technology
American Society of Mechanical Engineers
2006
Abstract
Free surface flows are frequently encountered in hydraulic engineering problems including water jets, weirs and around gates. An iterative solution to the incompressible two-dimensional vertical steady Navier-Stokes equations, comprising momentum and continuity equations, is used to solve for the priori unknown free surface, the velocity and the pressure fields. The entire water body is covered by a unstructured finite element grid which is locally refined. The dynamic boundary condition is imposed for the free surface where the pressure vanishes. This procedure is done continuously until the normal velocities components vanish. To overcome numerical errors and oscillations encountering in...
Laboratory Investigation of Hydraulic & Constructional Effect of Sills on Dissipation of Energy in the Stepped Spillway
, M.Sc. Thesis Sharif University of Technology ; shamsaee, Abolfazl (Supervisor)
Abstract
Chutes and stepped spillways are used to provide controlled release of flows and overflow in flood regimes from a dam into the downstream area. The main purpose of steps is to produce considerable energy dissipation along the chute and reduce the size of the required downstream energy dissipation basin. Many researches conducted on this matter and the effects of different factors like the height of steps, the number of steps, the different shapes of steps – mild step and end-sill step – influencing on energy dissipation have been studied. In this study, three different stepped spillway experimental models with different heights (5, 8 and 10 cm) and different number of steps developed, and...
The Effect of the Step Height on Energy Dissipation in Stepped Spillways Using Numerical Simulation
, Article Arabian Journal for Science and Engineering ; Vol. 39, issue. 4 , 2014 , p. 2587-2594 ; Hosseini, K ; Abdi, H ; Hosseini, M ; Sharif University of Technology
Abstract
From 1970s, studies have been conducted on the hydraulic design of stepped spillways and many empirical formulas were developed. Despite the simple geometry of these spillways, their hydraulic behavior is complicated. As a result, for many cases, the physical models are studied to verify the design. Numerical simulation is considered as a tool to reduce the laboratory tests, in order to save time and money. Furthermore, the parameters which are not investigated or measured in physical models could be evaluated. In this paper, the results of numerical simulations are compared with the results of physical models and empirical formulas for the spillway of Renwick dam studied in a 1/8 scale...
Numerical modeling of flow over a dam spillway
, Article 2006 2nd ASME Joint U.S.-European Fluids Engineering Summer Meeting, FEDSM 2006, Miami, FL, 17 July 2006 through 20 July 2006 ; Volume 2006 , 2006 ; 0791837831 (ISBN); 9780791837832 (ISBN) ; Shayanfar, M ; Jabbari, E ; Haji Mohammadi, M ; Sharif University of Technology
2006
Abstract
Free surface flows are frequently encountered in hydraulic engineering problems including water jets, weirs and around gates. An iterative solution to the incompressible two-dimensional vertical steady Navier-Stokes equations, comprising momentum and continuity equations, is used to solve for the priori unknown free surface, the velocity and the pressure fields. The entire water body is covered by a unstructured finite element grid which is locally refined. The dynamic boundary condition is imposed for the free surface where the pressure vanishes. This procedure is done continuously until the normal velocities components vanish. To overcome numerical errors and oscillations encountering in...
Lateral chute and jet impact for ogee spillway
, Article 31st IAHR Congress 2005: Water Engineering for the Future, Choices and Challenges, 11 September 2005 through 16 September 2005 ; 2005 , Pages 2609-2615 ; 8987898245 (ISBN); 9788987898247 (ISBN) ; Ahmadi, A ; Byong-Ho J ; Sang I. L ; Won S. I ; Gye-Woon C ; Sharif University of Technology
Korea Water Resources Association
2005
Abstract
Ogee spillway with lateral stepped chutes is a kind of compound spillway which, the energy dissipates due to spillway, turbulence in lateral step chutes and jets impact. Therefore, beside extra energy loss respect to conventional spillways, the Froude number at the foot of the spillway reduces dramatically comparing with the ordinary spillways and a smaller stilling basin is needed with reduced dimensions. In this study the performance of experimental model of this kind of spillway with two opposite symmetrical lateral chutes with different slopes and roughness has been studied. Five different widths for downstream channel (or chute slope), three different kinds of chute roughness (with...
Selection of empirical formulae for design of stepped spillways on RCC dams
, Article World Environmental and Water Resources Congress 2011: Bearing Knowledge for Sustainability - Proceedings of the 2011 World Environmental and Water Resources Congress, 22 May 2011 through 26 May 2011 ; May , 2011 , Pages 2508-2517 ; 9780784411735 (ISBN) ; Attari, J ; Sharif University of Technology
2011
Abstract
Stepped spillways have been widely used in Roller Compacted Concrete (RCC) dams in the recent decades. Considering complexity of hydraulics of stepped chutes, their initial design involves pre-selection of some empirical formulae for calculation of flow characteristics and design parameters. In this paper, accuracy of several empirical formulae, proposed for calculating locations of aeration inception (LI), uniform flow (Lu) and rate of energy dissipation (ΔH/Hmax), were compared in relation to results of physical model tests of four stepped spillways and the preferred formulae, providing least amounts of relative errors, were identified. Such a feedback will be helpful for improvement of...
Effects of anti-vortex plates on air entrainment by free vortex
, Article Scientia Iranica ; Volume 20, Issue 2 , 2013 , Pages 251-258 ; 10263098 (ISSN) ; Borghei, S. M ; Sharif University of Technology
2013
Abstract
Free surface vortex and air entrainment are not favorable experiences in hydropower and pumping projects. While complete omission of vortex and air entrainment is not always cost effective, partially weakened free-surface vortex flow is more economical and practical. Hence, in this study, a comprehensive set of experiments were conducted to partially reduce vortex strength and air entrainment at vertical pipe intakes, using rectangular anti-vortex plates. This phenomenon results in increasing water discharge compared with a corresponding free-surface vortex for the same water depth, i.e. in cases of shaft spillway. The plates were used as singles and in pairs and placed symmetrically and...
Numerical Simulation of Hydrodynamics of Flow over Gabion Stepped Weir
, M.Sc. Thesis Sharif University of Technology ; Shamsai, Abolfazl (Supervisor) ; Ghaemian, Mohsen (Co-Supervisor)
Abstract
The use of stepped weirs dates back at least 3500 years. In this research, the hydrodynamics of gabion stepped weirs have been investigated as a three-dimensional simulation of two-phase flow air-water using Flow3D software and the method of computational fluid dynamics (CFD) analysis. In order to solve the Reynolds-Averaged Navier-Stokes (RANS) equations, the RNG turbulence model (k-ε) was used and the free surface elevation of fluid was determined by the volume of fluid (VOF) method. The experimental results of Wutrish and Chanson (2014) over gabion stepped weirs are used to validate the numerical model simulations. Gabion stepped weirs with steps of 3, 7.5, and 10 cm in height, as well as...
Analysis of Factors Affecting Cavitation of Ogee Crested Spillway in Concrete Dams
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
In this study, the factors affecting cavitation in the crest of an ogee spillway were investigated. One of the factors affecting the occurrence of cavitation on the ogee crest is the ratio of the head to the design head. As the head ratio increases, the probability of cavitation on the crest increases. The value of the head is also an effective parameter for the occurrence of cavitation. The spillway crest curve is also one of the factors affecting the occurrence of cavitation on the ogee-crested spillways. In this study, the ogee crested spillway that consists of three circular arcs upstream has been investigated. 5 different head ratios have been used. For this study, OpenFOAM software,...