EXPERIMENTAL STUDY OF FLOW THROUGH TRAPEZOIDAL WEIR CONTROLLED UNDER A SEMI-CIRCULAR GATE

2021 ◽  
Vol 5 (2) ◽  
pp. 245-154
Author(s):  
Bashir Tanimu ◽  
Bilal Abdullahi Be ◽  
Muhammad Mujihad Muhammad ◽  
Surajo Abubakar Wada
Keyword(s):  
Experimental Study ◽  
Discharge Coefficient ◽  
Percentage Error ◽  
Nonlinear Regression Analysis ◽  
Block Model ◽  
Gate Structure ◽  
Flow Through ◽  
Mathematical Equations ◽  
Coefficient Of Discharge ◽  
Good Agreement

Different parameters of a weir model have a great effect on the discharge coefficient. In this experimental study the effect of varying angle of a trapezoidal weir coupled with a below semi-circular gate is determined. The result showed that the higher the value of  the higher the coefficient of discharge. The respective average discharge coefficient  of the block model and the trapezoidal weir models are; 0.48031,0.48880, 0.49565, 0.49647, 0.49892 and 0.49934. As such the trapezoidal weir with   has the highest value of average discharge coefficient =0.49934. Hence the most efficient. Linear and nonlinear regression analysis were used to generate mathematical equations that can be used to predict the flow rate Q for the combined weir-gate structure and the discharge coefficient  of the most efficient model with  respectively. The discharge coefficient for the most efficient weir model was found to be 3.81% more than that of the block model (with rectangular weir). The predicted coefficient of discharge   for the most efficient model was also found to be in good agreement with the observed discharge coefficient with a percentage error in the range of  0.4%

An experimental study of flow into orifices and grating inlets on streets

2006 ◽  
Vol 33 (7) ◽  
pp. 837-845 ◽  
Author(s):  
Z Mustaffa ◽  
N Rajaratnam ◽  
David Z Zhu
Keyword(s):  
Experimental Study ◽  
Froude Number ◽  
Specific Energy ◽  
Discharge Coefficient ◽  
Laboratory Scale ◽  
Scale Model ◽  
The Third ◽  
Flow Through ◽  
Coefficient Of Discharge ◽  
The City

Findings are described from a laboratory-scale model of flow through orifices on manhole covers and through three types of grating inlets used by the City of Edmonton. The results demonstrated that the flow through these orifices can be calculated using an orifice equation with a coefficient of discharge equal to 0.616 in a ponding situation but decreasing with an increase in the Froude number of the flow. The roughness of the manhole cover was found to slow down this reduction. For the three gratings, the inflow can be calculated with an orifice type of equation when the gratings are submerged. The discharge coefficient in this equation is approximately constant for two of the gratings and decreases somewhat with an increase in the Froude number of the flow for the third grating if the specific energy of the approaching flow is used as the length scale.Key words: street inlet, street hydraulics, grating inlet, orifice flows.

Steady Compressible Flow through a Single Row of Radial Holes in the Wall of a Pipeline

1970 ◽  
Vol 12 (4) ◽  
pp. 248-258 ◽  
Author(s):  
G. H. Trengrouse
Keyword(s):  
Discharge Coefficient ◽  
Pressure Change ◽  
Single Row ◽  
One Dimensional ◽  
Discharge Coefficients ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Flow Through ◽  
Flow Theories ◽  
Good Agreement

Measured values of discharge coefficient for air flow through a single row of radial holes in the wall of a pipeline are reported, together with the values of pipe Mach numbers in the immediate vicinity of the holes. A wide range of pressure and area ratios are considered, the flow through the holes being either into or out of the pipe. It is shown that the effects on the measured values of both the pressure level at discharge from the holes and the air temperature are negligible. The agreement between the pressure change in the pipeline due to the holes, obtained experimentally, and that predicted by simple, one-dimensional flow theories is generally unsatisfactory. However, theoretical predictions of the jet efflux angles based on two-dimensional, incompressible, non-viscous flow arguments are in good agreement with those measured, but discrepancies do arise in the prediction of discharge coefficients.

scholarly journals Inlet and Exit-Header Shapes for Uniform Flow Through a Resistance Parallel to the Main Stream

1961 ◽  
Vol 83 (3) ◽  
pp. 361-368 ◽  
Author(s):  
Morris Perlmutter
Keyword(s):  
Experimental Study ◽  
Pressure Drop ◽  
Total Pressure ◽  
Experimental Results ◽  
Main Stream ◽  
Height Ratio ◽  
Large Length ◽  
Flow Through ◽  
Pass Through ◽  
Good Agreement

An analytical and experimental study of flow in headers with a resistance parallel to the turbulent and incompressible main stream has been made. The purpose was to shape the inlet and exit headers, which had a large length-to-height ratio, so that the fluid would pass through the resistance uniformly. Analytical wall shapes and estimated total pressure drop through the headers were compared with experimental results. Good agreement between analysis and experiment was found for the cases compared.

A Theory of Sharp-Edged Orifices

1937 ◽  
Vol 4 (2) ◽  
pp. A53-A54
Author(s):  
W. E. Howland
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Discharge Coefficient ◽  
Reynolds Numbers ◽  
Experimental Results ◽  
Low Reynolds Numbers ◽  
Circular Orifice ◽  
Coefficient Of Discharge ◽  
Theoretical Considerations ◽  
Good Agreement

Abstract The author presents a figure in which the coefficient of discharge Cd, velocity Cv, and contraction Cc determined by several investigators are plotted logarithmically as points against Reynolds’ numbers. Curves for the coefficients drawn by the author, based on theoretical considerations, show good agreement with the experimental data, thus throwing some light upon the basic phenomena of the discharge of sharp-edged orifices. The variation of the coefficient of discharge of a circular orifice as a function of the Reynolds number is explained as a purely viscous phenomenon for low Reynolds numbers, and by means of a momentum analysis for higher speeds. The analysis presented by the author leads to the development of several formulas for the discharge coefficient, which formulas are in fair agreement with experimental results.

scholarly journals Discharge coefficient of flow over Al-Shalalat stepped weir on Al-Khusr River

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Azza N. Altalib
Keyword(s):  
Energy Dissipation ◽  
Discharge Coefficient ◽  
Open Channel ◽  
Hydraulic Structures ◽  
Percentage Error ◽  
Hydraulic Characteristics ◽  
Irrigation Channels ◽  
Different Shapes ◽  
Coefficient Of Discharge ◽  
Discharge Measurements

AbstractMany hydraulic structures are constructed in an open channel according to the purposes and the nature of the region. Weir is one of these structures which is used for discharge measurements as well as rising water depth in irrigation channels. According to the crest, there are two different shapes: sharp and broad crested weir. A stepped weir is constructed to reduce scour that happened downstream. There are different studies dealt with discharge coefficient, energy dissipation, and other hydraulic characteristics for flow over the weir. In this study, the coefficient of discharge for the Al-Shalalat stepped weir on the Al-Khusr River has been evaluated. The discharge coefficient equation is predicted, and the result values are compared with previous studies. The percentage error for the predicted discharge equation presented in this study compared with previous studies does not exceed 10%.

Fluid Flow in Perforated Pipes

1975 ◽  
Vol 17 (6) ◽  
pp. 338-347 ◽  
Author(s):  
B. J. Bailey
Keyword(s):  
Fluid Flow ◽  
Discharge Coefficient ◽  
Static Pressure ◽  
Pipe Wall ◽  
Air Flow ◽  
Diameter Ratio ◽  
Friction Loss ◽  
Flow Through ◽  
Good Agreement ◽  
Air Discharge

Values of the discharge coefficient for air flow through single holes in a pipe wall, and for the angle of efflux are reported. The variation of static pressure along tubular polyethylene air ducts with a maximum length-to-diameter ratio of 250 containing pairs of diametrically opposed holes has been measured. This information was used with data on friction loss to determine values for the coefficient of static pressure regain. It was possible to predict variations in static pressure and air discharge along uniformly perforated ducts which were in good agreement with those observed experimentally.

Numerical Predictions and Measurements of Discharge Coefficients in Labyrinth Seals

1987 ◽  
Author(s):  
S. Wittig ◽  
U. Schelling ◽  
S. Kim ◽  
K. Jacobsen
Keyword(s):  
Discharge Coefficient ◽  
Test Facility ◽  
Geometrical Parameters ◽  
Two Dimensional ◽  
Labyrinth Seals ◽  
Discharge Coefficients ◽  
Numerical Predictions ◽  
Flow Through ◽  
Compressible Turbulent Flow ◽  
Good Agreement

The present paper illustrates the possibilities and limitations in applying advanced numerical codes for the description of the flow through labyrinth seals to evaluate the discharge coefficient. Comparison with data derived from detailed measurements in a newly developed test facility are reported. Pressure ratios and geometrical parameters are varied in wide ranges, reflecting engine conditions. The two-dimensional, elliptic finite difference code is applied to the compressible, turbulent flow in straight and stepped seals utilizing the standard k-ε-model. Good agreement of the predictions with the measurements is achieved for pressure ratios up to 2.5.

Experimental study of one- and two-cycle trapezoidal piano-key side weirs in a curved channel

2019 ◽  
Vol 19 (6) ◽  
pp. 1597-1603 ◽  
Author(s):  
Abolfazl Saghari ◽  
Mojtaba Saneie ◽  
Khosrow Hosseini
Keyword(s):  
Experimental Study ◽  
Dimensional Analysis ◽  
Discharge Capacity ◽  
Discharge Coefficient ◽  
Empirical Equation ◽  
Measured Data ◽  
Total Width ◽  
Curved Channel ◽  
Side Weirs ◽  
Good Agreement

Abstract Piano-key weirs can be used instead of classic rectangular side-weirs (CRSWs) to increase the discharge capacity of side weirs. So far, no research has been done on trapezoidal piano-key side weirs (TPKSWs) in a curved channel. This study examines the effect of using one or two cycles in TPKSWs on discharge capacity, having the same total width and upstream–downstream length. Dimensional analysis has been performed to determine the dimensionless parameters affecting the discharge coefficient related to the developed length (CdL) of TPKSWs in a curved channel. An empirical equation for CdL has been proposed based on the experimental results. There is a good agreement between estimated and measured data. Results showed that the discharge coefficient related to the total width of a TPKSW is 1.7 to 5.6 times higher than that of a CRSW. Also, the CdL of a one-cycle TPKSW is 1.4 to 2 times higher than that of a two-cycle TPKSW.

Correlations for the discharge coefficient of rotating orifices based on the incidence angle

2005 ◽  
Vol 219 (5) ◽  
pp. 333-352 ◽  
Author(s):  
A Idris ◽  
K. R. Pullen
Keyword(s):  
Fluid Dynamics ◽  
Reynolds Number ◽  
Discharge Coefficient ◽  
Incidence Angle ◽  
Pressure Ratio ◽  
Cross Flow ◽  
Flow Parameters ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
Good Agreement

The flow through rotating orifices is of interest to the designer of machines incorporating such features. The designer often requires a set of correlations which can be used to check out preliminary designs and converge on a solution prior to attempting detailed and expansive analysis. The correlations given in this paper are based on the incidence angle, i, of the flow into the orifice and they allow the discharge coefficient for rotating orifices to be estimated for as many conditions and geometries as possible. The approach adopted is to group the parameters that affect the discharge coefficient to i = 0° (Reynolds number, orifice chamfer and radius, L/d ratio, pressure ratio, and pumping effect) and i ≠ 0° (rotation of the disc, preswirl, cross-flow, and the angle of inclination of the orifice). The effect of each parameter on the discharge coefficient can easily be observed when using this method. Furthermore, the method can predict the discharge coefficient for systems that have various parameters that are combined together. There is a good agreement between the correlations and the experimental results and the available data on rotating orifices in the open literature. The correlations also agree with various combinations run in computational fluid dynamics (CFD). The approach adopted in this paper, which is based on the incidence angle, can assist designers to find the combination of geometric and flow parameters that gives the best discharge coefficient for rotating orifices.

Upward Vertical Two-Phase Flow Through an Annulus—Part II: Modeling Bubble, Slug, and Annular Flow

1992 ◽  
Vol 114 (1) ◽  
pp. 14-30 ◽  
Author(s):  
E. F. Caetano ◽  
O. Shoham ◽  
J. P. Brill
Keyword(s):  
Flow Pattern ◽  
Annular Flow ◽  
Two Phase Flow ◽  
Flow Behavior ◽  
Bubble Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Through ◽  
Physical Phenomena ◽  
Good Agreement

Mechanistic models have been developed for each of the existing two-phase flow patterns in an annulus, namely bubble flow, dispersed bubble flow, slug flow, and annular flow. These models are based on two-phase flow physical phenomena and incorporate annulus characteristics such as casing and tubing diameters and degree of eccentricity. The models also apply the new predictive means for friction factor and Taylor bubble rise velocity presented in Part I. Given a set of flow conditions, the existing flow pattern in the system can be predicted. The developed models are applied next for predicting the flow behavior, including the average volumetric liquid holdup and the average total pressure gradient for the existing flow pattern. In general, good agreement was observed between the experimental data and model predictions.

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