On the Effects of Water Discharge Through Radial Gates at the Caruachi Dam

2010 ◽  
Author(s):  
Douglas Sanchez ◽  
Juan E. Salazar
Keyword(s):  
Water Flow ◽  
Water Discharge ◽  
Three Dimensional ◽  
Flow Induced Vibration ◽  
Discharge Flow ◽  
Cfd Models ◽  
Flow Through ◽  
Critical Velocities ◽  
Flow Effects

This paper presents numerical simulation of the water flow through the radial gates of the 2,280 MW Caruchi Dam, in southern Venezuela, and its relation to the vibration of the dam’s spillways and adjacent Control Building. The study is conducted as a contribution in determining the source of vibration of the fore mentioned structures in the case of gates opening above the normal values of up to 5 m, which occur when a larger water discharge is required in order to maintain an adequate level of the reservoir during the rainy season. The aim of the study was to find the pressure distribution and velocity profiles of the discharge flow through one of the dam’s radial gates and determine critical (reduced) velocities that may result in flow-induced vibration of the gates, as they were deemed to be the source of vibration of the whole set of structures in the first place. For this purpose, a commercially available FEM code was used. Three-dimensional CFD models were developed to simulate behavior of the flow when being released to the spillways, for opening values of 2, 5, 10 and 14 m, including the effect of the spillways’ deflectors. Modal analyses of the gate were performed, to take into account natural vibration frequencies in the determination of its critical velocities. After comparison of the gate’s critical velocities and velocity values from the CFD simulations, it is fair to say that the discharge flow does not directly induce vibration on the gates but rather on the spillways’ structure. This conclusion disregards flow through the gates as triggering the vibration phenomena which gave origin to this project, and puts the emphasis now on studying water flow effects on vibration in the spillway which, if not corrected on time, may ultimately lead to its catastrophic failure.

Ponded infiltration into soil with biopores — field experiment and modeling

Biologia ◽  
2009 ◽  
Vol 64 (3) ◽  
Author(s):  
Michal Dohnal ◽  
Jaromír Dušek ◽  
Tomáš Vogel ◽  
Milena Císlerová ◽  
Ľubomír Lichner ◽  
...  
Keyword(s):  
Water Flow ◽  
Preferential Flow ◽  
Water Pressure ◽  
Three Dimensional ◽  
Detailed Knowledge ◽  
Dye Tracer ◽  
Simulation Based ◽  
Flow Through ◽  
Flow Effects ◽  
Infiltration Experiment

AbstractPreferential movement of water in macropores plays an important role when the process of ponded infiltration in natural porous systems is studied. For example, the detailed knowledge of water flow through macropores is of a major importance when predicting runoff responses to rainfall events. The main objectives of this study are to detect preferential movement of water in Chernozem soil and to employ numerical modeling to describe the variably saturated flow during a field ponded infiltration experiment. The infiltration experiment was performed at the Macov experimental station (Calcari-Haplic Chernozem in Danubian Lowland, Slovakia). The experiment involved single ring ponded infiltration. At the quasi steady state phase of the experiment dye tracer was added to the infiltrating water. Then the soil profile was excavated and the penetration pattern of the applied tracer was recorded. The abundance of biopores as a product of fauna and flora was found. To quantify the preferential flow effects during the infiltration experiment, three-dimensional axisymmetric simulations were carried out by a two-dimensional dual-continuum numerical model. The water flow simulations based on measured hydraulic characteristics without consideration of preferential flow effects failed to describe the infiltration experiment adequately. The 3D axisymmetric simulation based on dual-permeability approach provided relatively realistic space-time distribution of soil water pressure below the infiltration ring.

scholarly journals Determination of cross-sectional void fraction in a two-phase water flow through a PVC pipe

2021 ◽  
Vol 655 (1) ◽  
pp. 012024
Author(s):  
O.H. Ajesi ◽  
M.B. Latif ◽  
S.T. Gbenu ◽  
C. A. Onumejor ◽  
M. K. Fasasi ◽  
...  
Keyword(s):  
Water Flow ◽  
Void Fraction ◽  
Two Phase ◽  
Cross Sectional ◽  
Flow Through ◽  
Pvc Pipe ◽  
Phase Water

Glaciohydraulic supercooling: a freeze-on mechanism to create stratified, debris-rich basal ice: II. Theory

1998 ◽  
Vol 44 (148) ◽  
pp. 563-569 ◽  
Author(s):  
Richard B. Alley ◽  
Daniel E. Lawson ◽  
Edward B. Evenson ◽  
Jeffrey C. Strasser ◽  
Grahame J. Larson
Keyword(s):  
Water Flow ◽  
Accretion Rate ◽  
Water Discharge ◽  
Steep Slope ◽  
Field Observations ◽  
Ice Accretion ◽  
Flow Paths ◽  
Basal Ice ◽  
Flow Through ◽  
Pressure Melting

AbstractSimple theory supports field observations (Lawson and others, 1998 that subGlaciol water flow out of overdeepenings can cause accretion of layered, debris-bearing ice to the bases of glaciers. The large meltwater flux into a temperate glacier at the onset of summer melting can cause rapid water flow through expanded basal cavities or other flow paths. If that flow ascends a sufficiently steep slope out of an overdeepèning, the water will supercool as the pressure-melting point rises, and basal-ice accretion will occur. Diurnal, occasional or annual fluctuations in water discharge will cause variations in accretion rate, debris content of accreted ice or subsequent diagenesis, producing layers. Under appropriate conditions, net accretion of debris-bearing basal ice will allow debris fluxes that are significant in the glacier sediment budget.

Glaciohydraulic supercooling: a freeze-on mechanism to create stratified, debris-rich basal ice: II. Theory

1998 ◽  
Vol 44 (148) ◽  
pp. 563-569 ◽  
Author(s):  
Richard B. Alley ◽  
Daniel E. Lawson ◽  
Edward B. Evenson ◽  
Jeffrey C. Strasser ◽  
Grahame J. Larson
Keyword(s):  
Water Flow ◽  
Accretion Rate ◽  
Water Discharge ◽  
Steep Slope ◽  
Field Observations ◽  
Ice Accretion ◽  
Flow Paths ◽  
Basal Ice ◽  
Flow Through ◽  
Pressure Melting

AbstractSimple theory supports field observations (Lawson and others, 1998 that subGlaciol water flow out of overdeepenings can cause accretion of layered, debris-bearing ice to the bases of glaciers. The large meltwater flux into a temperate glacier at the onset of summer melting can cause rapid water flow through expanded basal cavities or other flow paths. If that flow ascends a sufficiently steep slope out of an overdeepèning, the water will supercool as the pressure-melting point rises, and basal-ice accretion will occur. Diurnal, occasional or annual fluctuations in water discharge will cause variations in accretion rate, debris content of accreted ice or subsequent diagenesis, producing layers. Under appropriate conditions, net accretion of debris-bearing basal ice will allow debris fluxes that are significant in the glacier sediment budget.

Pressure Drops of Water Flow Through Micromachined Particle Filters

2002 ◽  
Vol 124 (4) ◽  
pp. 1053-1056 ◽  
Author(s):  
Tzung K. Hsiai ◽  
Sung Kwon Cho and ◽  
Joon Mo Yang ◽  
Xing Yang and ◽  
Yu-Chong Tai ◽  
...  
Keyword(s):  
Water Flow ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Side Wall ◽  
Micro Electro Mechanical System ◽  
Numerical Code ◽  
Power Requirement ◽  
Pressure Drops ◽  
Flow Through ◽  
Wall Profile

When the particle is in the order of microns, flow through the small opening produces a large velocity gradient, leading to high viscous dissipation. Understanding the flow field is critical in determining the power requirement. In this paper, we studied water flow through filters fabricated by micro-electro-mechanical system (MEMS) techniques. The pressure drop calculated by a three-dimensional numerical code of the Navier-Stokes equations is in a resonable agreement with the experimental data if the diameter and the side wall profile of the holes are measured with high accuracy.

Analysis on Hydrodynamic Load that Induces High Dam Body Vibration

2014 ◽  
Vol 580-583 ◽  
pp. 1812-1815
Author(s):  
Chun Tao Wang ◽  
Hong Xia Ding ◽  
Hui Lv
Keyword(s):  
Water Flow ◽  
Back Analysis ◽  
Wall Pressure ◽  
Arch Dam ◽  
Shock Load ◽  
Flow Induced Vibration ◽  
Discharge Flow ◽  
Plunge Pool ◽  
Flood Discharge ◽  
The Impact

It is difficult to get a theoretic answer to the water flow load features of high dam flood discharge. Through direct measurement of water flow load features by arranging a surface pressure cell, the complicated point-surface conversion was avoided, and the shock load and surge load features were obtained. For the dam body outlet wall pressure, isolated the fluctuating load applied to the plunge pool floor and the downstream dam surface, the impact of the fluctuating load to the arch dam dynamic response at the flood discharge flow outlet was obtained, and then the equivalent fluctuating load on each discharge flow outlet was obtained by using flow-induced vibration back analysis. The test shows that the energy of the shock load and the surge load mainly centers in a frequency range between 0~1Hz, the shock load is about 2.5-6 times that of the surge load, and the surge load is about 4 times that of the outlet wall pressure.

Bestimmung von Reflexionskoeffizienten an der Membran der Alge Valonia utricularis / Determination of Reflection Coefficients of the Membrane of the Algae Valonia utricularis

1970 ◽  
Vol 25 (5) ◽  
pp. 500-504 ◽  
Author(s):  
U. Zimmermann ◽  
E. Steudle
Keyword(s):  
Hydrostatic Pressure ◽  
Osmotic Pressure ◽  
Water Flow ◽  
Linear Dependence ◽  
Volume Flow ◽  
Reflection Coefficients ◽  
Valonia Utricularis ◽  
Flow Through ◽  
Zero Flow

A zero flow method of rapidly determining reflection coefficients of giant algae cells is described.Changes of the osmotic pressure in the outside medium caused a net volume flow through the cell membranes and consequently changes of the hydrostatic pressure inside the cell. By continously measuring the hydrostatic pressure it was possible, to determine the concentration outside the cell at which no volume flow occurs.The reflection coefficients of some non-electrolyts were determined on the membrane of the mediterranean algae Valonia utricularis with an error of 3 - 4% and are discussed on the basis of the pore model.The hydrostatic pressure inside Valonia cells decreased exponentially with time, when they were put into a hypertonic aequous solution. If a linear dependence of the volume (water) flow on the hydrostatic and osmotic pressure differences is supposed, it will be possible to calculate the volume (water) flow.

scholarly journals Flood threat to the territories below the water dam in conditions of occurrence of extreme hydrological phenomena

2009 ◽  
Vol 41 (1) ◽  
pp. 57-69
Author(s):  
Marek Madeyski ◽  
Bogusław Michalec ◽  
Marek Tarnawski
Keyword(s):  
Water Management ◽  
Water Level ◽  
Channel Capacity ◽  
Water Discharge ◽  
Water Reservoir ◽  
Discharge Flow ◽  
Maximum Water ◽  
The Difference

Flood threat to the territories below the water dam in conditions of occurrence of extreme hydrological phenomena The course of the flood in July 2001 and passage of the freshet wave through the water reservoir Chańcza on the Czarna Staszowska River was analyzed. Culmination of this wave equaling 418.62 m3·s-1 was two times higher than the estimated flow of 1% probability for what the reservoir was designed. Water management during the flood forced a higher than forecast water discharge during culmination. The paper aims at determination of water level situation on the territory at maximum water discharge from the reservoir during the flood equaling 122.75 m3·s-1 and showing possibilities of flood threat reduction. The range of the inundation zone at this discharge flow on the territory below the dam at the length of 3 km was determined taking into regard the influence of vegetation in the valley and in the zone adjacent the channel and bridge. The cause of inundation of the valley on the studied river sector is a rather low channel capacity equaling from 20-60 m3·s-1. It was found that the bridge does not influence the leveling of the analyzed flow and the reserve in the bridge light, determined as the difference of ordinate of the underlay of the span beam and ordinate of the water level under the bridge 0.92 m. Calculations of the channel capacity were also carried out in the case of renovation treatments consisting in removing stiff and soft vegetation and decrease in the inundation range of the valley was demonstrated.

Numerical Simulation of Flow Through Nuclear Fuel Bundles With Angular Misalignments

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
A. Bhattacharya ◽  
S. D. Yu
Keyword(s):  
Nuclear Fuel ◽  
Large Scale ◽  
Computational Models ◽  
Three Dimensional ◽  
Cross Flow ◽  
Eddy Simulation ◽  
Cfd Models ◽  
Fuel Bundle ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through

Comprehensive computational fluid dynamics (CFD) models are developed and analyzed in this paper to study the three-dimensional flow through simulated nuclear fuel bundles with angular misalignments inside a pressure tube. The large eddy simulation (LES) scheme is employed to solve the large scale complex computational models with an aim to understanding the effects of the bundle-to-bundle angular misalignments on unsteady flow and flow-induced excitations on the fuel bundle structures. The proposed numerical scheme is validated with both numerical and experimental work available in the literature. Numerical results obtained from the current computational models indicate the presence of significant lateral or cross-flow in the bundle-to-bundle interface region for bundles with angular misalignments. The mean and the rms values of the lateral fluid excitations on the first bundle are found to be sensitive with respect to the change in angular misalignments between bundles.

scholarly journals ANALYSIS OF FLOW THROUGH A DOUBLE-ACTING IMPELLER WITH A STRAIGHT RADIAL BLADES USING CFD

2013 ◽  
pp. 257-263
Author(s):  
SUTHEP. KAEWNAI ◽  
SOMCHAI WONGWISES
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Initial Conditions ◽  
Volume Flow Rate ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Flow State ◽  
Total Head ◽  
Third Stage ◽  
Flow Through

This study aims to analyze water flow through a centrifugal pump with straight radial blades double-acting impeller using computational fluid dynamics (CFD). The impeller analyzed was designed with the following conditions: a volume flow rate of 33.5 m3/h, head of 100 m, rotational speed of 2,950 rpm, and specific speed of 9. The first stage began with calculations for various dimensions of double-acting isolated impeller and impeller-collector assembly, followed by three-dimensional drawing and domain specification. In the second stage, grids for the isolated impeller and impellercollector assembly were generated. In the third stage, the initial conditions and boundary conditions were specified. Finally, the water flow through the isolated impeller and impeller-collector assembly was analyzed using the CFX 13 code to predict the water flow state. A fluid dynamic analysis of the isolated impeller and impeller-collector assembly reveals that the Q-H curve rises continuously toward shutoff as the flow rate is reduced. The results indicate that the total head rise of the isolated impeller is approximately 98.8 m for a 65 mm impeller inlet width and 99.89 m for a 70 mm impeller inlet width. This may be due to reduced circulation between blade passages of impeller. Similar to the isolated impeller, the Q-H curve of the impeller-collector assembly also rises continuously toward shutoff as the flow rate is reduced. The total head rise is reduced to approximately 98 m because of losses in the collector. Concerning the flow in the impeller-collector assembly when Q / Q design is or less than 1.0, the pressure distribution is high at the tongue of collector. Concerning the velocity distribution when Q / Q design is more or less than 1.0, there is circulation or a vortex at the top of the collector.

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