Computational Study of the Downpull Force on High-Head Slide Gates

2019 ◽  
Author(s):  
Juan C. Arango Escobar ◽  
David Calderon Villegas ◽  
Aldo Benavides Moran ◽  
Alejandro Molina Ochoa
Keyword(s):  
Computational Study ◽  
Maximum Flow ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Cfd Simulations ◽  
Ansys Fluent ◽  
Flow Through ◽  
High Head ◽  
The One ◽  
Bottom Outlet

Abstract This paper presents CFD simulations of the flow through a real bottom outlet equipped with high-head slide gates. The operating head of the gates and the maximum flow rate are 70 m and 650 m3/s, respectively. The numerical simulations were performed in ANSYS-FLUENT version 19.2. VOF method was used to model the free surface flow downstream the slide gates. Hydrodynamic forces were calculated at nine gate openings for a standard 45° lip gate; the downpull coefficients obtained from the simulations were compared with estimates from Naudascher’s analytical method. According to the CFD results, the downpull force acting on the 45° lip gate is 5%–10% lower than the one estimated analytically for the analyzed gate positions. Additionally, the flow through an inverted 30° lip gate was simulated to estimate the downpull coefficient at various gate openings. These coefficients cannot be determined analytically. The methodology here described can easily be applied to different gate geometries for which design coefficients are not available.

An approach to simulation of dual drainage

1999 ◽  
Vol 39 (9) ◽  
pp. 95-103 ◽  
Author(s):  
S. Djordjević ◽  
D. Prodanović ◽  
Č. Maksimović
Keyword(s):  
Numerical Model ◽  
Model Development ◽  
Ground Level ◽  
Surface Flow ◽  
Surface Excess ◽  
Runoff Simulation ◽  
Sewer System ◽  
Excess Water ◽  
Flow Through ◽  
The One

The paper presents the development of the field of urban drainage modelling known as dual drainage - an approach to rainfaill runoff simulation in which the numerical model takes into account not only the flow through the sewer system, but also the flow on the surface. The steps in model development are described, and necessary data, assumptions used and operations to be performed using GIS are discussed. The numerical model simultaneously handles the full dynamic equations of flow through the sewer system and simplified equations of the surface flow. The surface excess water (due to the limited capacity of inlets or to the hydraulic head in the sewer system reaching the ground level) is routed to the neighbour subcatchment (not necessarily the one attached to the downstream network node), using surface retentions, if any.

scholarly journals A computational investigation of the hydrodynamics of the Badush dam in northern Iraq

2018 ◽  
Vol 240 ◽  
pp. 04009
Author(s):  
Younis Saida Saeedrashed ◽  
Ali Cemal Benim
Keyword(s):  
Three Dimensional ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Dam Failure ◽  
Northern Iraq ◽  
Digital Elevation ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
Elevation Model ◽  
Bottom Outlets

A computational analysis of the hydrodynamics of the Badush dam in Iraq is presented, which is planned to be reconstructed as a repulse dam, to prevent the Mosul city, in case of a failure of the Mosul dam. Computational Fluid Dynamics (CFD) is applied in combination with Geometric Information System (GIS) and Digital Elevation Model (DEM). In the first part of the study, a hydrologic study of a possible Mosul dam failure is performed, predicting the important parameters for a possible flooding of Mosul city. Here, a two-dimensional, depth-averaged shallow water equations are used to formulate the flow. Based on GIS and DEM, the required reservoir size and the water level of the Badush dam are predicted, for its acting as a repulse dam. Subsequently, a computational model of the reconstructed Badush dam is developed, combining the proposed construction with the local geographic topology to achieve a perfect fit. Finally, the water flow through the bottom outlets and stilling basin of the proposed dam is calculated by an unsteady, three-dimensional CFD analysis of the turbulent, free-surface flow. The CFD model is validated by comparing the predictions with measurements obtained on a physical model, where a quite satisfactory agreement is observed.

CFD Simulations of Unsteady Wakes on a Highly Loaded Low Pressure Turbine Airfoil (L1A)

2012 ◽  
Author(s):  
Mounir B. Ibrahim ◽  
Samuel Vinci ◽  
Olga Kartuzova ◽  
Ralph J. Volino
Keyword(s):  
Computational Study ◽  
Separation Bubble ◽  
Low Pressure ◽  
Flow Coefficient ◽  
Freestream Turbulence ◽  
Suction Surface ◽  
Cfd Simulations ◽  
Ansys Fluent ◽  
Low Pressure Turbine ◽  
Wake Passing

A study of a very high lift, low-pressure turbine airfoil in the presence of unsteady wakes was performed computationally and compared against experimental results. The experiments were conducted in a low speed wind tunnel under high (4.9%) and then low (0.6%) freestream turbulence intensity conditions with a flow coefficient (ζ) of 0.7. The experiments were done on a linear cascade with wakes that were produced from moving rods upstream of the cascade with the rod to blade spacing varied from 1 to 1.6 to 2. In the present study two different Reynolds numbers (25,000 and 50,000, based on the suction surface length and the nominal exit velocity from the cascade) were considered. The experimental and computational data have shown that in cases without wakes, the boundary layer separated and did not reattach. The CFD was performed with Large Eddy Simulation (LES) and Unsteady Reynolds-Averaged Navier-Stokes (URANS), Transition-SST, utilizing the finite-volume code ANSYS FLUENT under the same freestream turbulence and Reynolds number conditions as the experiment but only at a rod to blade spacing of 1. With wakes, separation was largely suppressed, particularly if the wake passing frequency was sufficiently high. Similar effect was predicted by 3D CFD simulations. Computational results for the pressure coefficients and velocity profiles were in a reasonable agreement with experimental ones for all cases examined. The 2D CFD efforts failed to capture the three dimensionality effects of the wake and thus were less consistent with the experimental data. As a further computational study, cases were run to simulate higher wake passing frequencies which were not run experimentally. The results of these computational cases showed that an initial 25% increase from the experimental dimensionless wake passing frequency of F = 0.45 greatly reduced the size of the separation bubble, nearly completely suppressing it, however an additional 33% increase on top of this did not prove to have much of an effect.

scholarly journals Computational Study to Predict the Free-Surface Flow over Non-uniform Stepped Spillway Using ANSYS-CFX

2020 ◽  
Vol 10 (1) ◽  
pp. 43-50
Author(s):  
Shawnm M. Saleh ◽  
Sarhang M. Husain
Keyword(s):  
Free Surface ◽  
Computational Study ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Stepped Spillway ◽  
Step Size ◽  
Stepped Spillways ◽  
Ansys Cfx ◽  
Long Time ◽  
Stepped Cascade

Using stepped chutes as a structure for controlling flood discharges is applicable for long time. Measuring the depth of flow over that structure is essential for designing of the side walls. The aim of this paper is to determine the free-surface that flows on spillway equipped with non-uniform step sizes. For that purpose, the two-dimensional software package code of ANSYS-CFX has been utilized to run eight configurations of two moderate slopes (1V:2H and 1V:2.5H) and for four different discharges 1≤dc/hs≤2.2 to determine the effect of flow discharges, chute slopes, and step heights on the position of free surface along the structure over non-uniform stepped cascade. The hexahedral grid size of 0.015 m is selected with inflation technique close to the walls. In addition, the renormalized group of k-ε (RNG) turbulence model is implemented and the numerical volume of fluid software is employed. The results show smoother stream for higher discharges, and the free-surface drops when the slope of chutes increases. Moreover, it is found that the step size has insignificant effect on the depth of water. The results of this study are important because they provide new insight in improving the design of stepped spillways. It is recommended to perform more investigations to evaluate their effectiveness in other flow parameters including pressure distribution and energy dissipation rates.

Multiphase modeling of the free surface flow through a Darrieus horizontal axis shallow-water turbine

2019 ◽  
Vol 143 ◽  
pp. 1890-1901 ◽  
Author(s):  
Alla Eddine Benchikh Le Hocine ◽  
R.W. Jay Lacey ◽  
Sébastien Poncet
Keyword(s):  
Free Surface ◽  
Shallow Water ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Horizontal Axis ◽  
Multiphase Modeling ◽  
Water Turbine ◽  
Flow Through

A MESHLESS METHOD FOR FREE SURFACE FLOW THROUGH SLUICE GATES

2004 ◽  
pp. 71-78 ◽  
Author(s):  
F. DANESHMAND ◽  
M. J. KAZEMZADEH-PARSI
Keyword(s):  
Free Surface ◽  
Meshless Method ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Flow Through

Free surface flow through rock-fill dams analyzed by FEM with level set approach

2001 ◽  
Vol 27 (3) ◽  
pp. 233-243 ◽  
Author(s):  
N. H. Sharif ◽  
N.-E. Wiberg ◽  
M. Levenstam
Keyword(s):  
Free Surface ◽  
Level Set ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Rock Fill ◽  
Flow Through ◽  
Level Set Approach

scholarly journals Approach to 3D Unsteady CFD Analysis of a Single-Blade Pump

2020 ◽  
Vol 328 ◽  
pp. 02016
Author(s):  
Kurilla Matej ◽  
Knížat Branislav ◽  
Olšiak Róbert
Keyword(s):  
Cfd Simulation ◽  
Centrifugal Pumps ◽  
Cfd Simulations ◽  
Ansys Fluent ◽  
Ansys Cfx ◽  
Hydraulic Machines ◽  
Element Number ◽  
The One ◽  
User Friendly ◽  
Blade Pump

Single-blade centrifugal pumps are hydraulic machines used in many industrial areas. A unique screw shaped blade enables liquids containing solids and fibrous matters to be pumped. Owing to good pump hydraulic properties on the one hand and unfavourable impeller mechanical properties on the other have single-blade pumps become recently more interesting for researchers regarding the CFD simulations. In this case a conventional CFD approach for multi-blade pumps cannot be applied due to the lack of symmetry of the single-blade impeller. Possible approaches to the CFD simulation of a single-blade impeller in the Ansys Fluent and the Ansys CFX are compared in this paper. A comparison of two CFD meshing tools showed substantial element number decrease of the whole CFD model. This paper presents also the laboratory experiment results of the investigated single-blade pump. The paper describes a new approach to the single-blade CFD simulation through Ansys Fluent which is faster and more user-friendly then the conventional approach.

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