Published Journal Articles
2021
Experimental Verification And Review Performance of The Modified Triangular Plan Form Weir
2021-01
Journal of University of Duhok (Issue : 2) (Volume : 23)
Weirs are discharge measurement structures have different geometrical shapes. The performances of
the modified triangular plan form weirs were studied under free-flow condition. Three groups of weirs
were tested experimentally. The first group has a flat top; the second has one slope and the third has two
slopes. Each group has three vertex angles (60o
, 90o
and 120o
) with constant height. The hydraulic
performances of weirs are based on the ability to pass the discharge for certain head flow and on the value
of the coefficient of discharge. The values of discharge and the coefficient were compared with earlier
studies being carried on conventional normal weir, broad crest, triangular plan-form and different
labyrinth weirs. All the groups show better performance than conventional shaped and broad weir. The
magnification of the actual discharge to the discharge of broad crested weir is more than one and the best
one is the first in the third group, while the vertex angle is (60o
) for the second and third group and (120o
)
for the first. The performance of the third group is better than rectangular labyrinth weirs, and it is
compatible with the triangular labyrinth. The discharge coefficient decreases with the increase of relative
value of the head to the height of weir except for the first group. Equations for predicting coefficient of
discharge are proposed within the limitations of this test.
2016
Stripped Bed Roughness Effect on Flow Measurement in Trapezoidal Channels with Free Overfalls
2016-07
ZANCO Journal of Pure and Applied Sciences (Issue : 27) (Volume : 2)
The aim of the present investigation is to study the effects of side slope, bed slope and bed roughness on the flow over free overfalls in trapezoidal channels. Three models of trapezoidal free overfall channels have been built and tested in a laboratory flume; each model had four different bed slopes. For each slope, the bed was roughened using artificial strip roughness elements with eight different roughness patterns. The experimental testing program included ninety-six series of experiments for different ranges of Froude number. Experimental results of all models showed that the variation of (πΈππ.π/βπππ) with (πππ/π) for different bed slopes and various roughness patterns is simple power equation. It was also observed that values of (πΈππ.π/βπππ) increase with the increase of (πππ/π) values. The correlation between (πππ/π) with (πππ/π) was found to be linear for different bed slopes and roughness patterns. The ratio (ππ/ππ) decreases with the increase of bed slope (S). An empirical expression was obtained for the variation of (πΈππ.π/βπππ) with (πππ/π) and (S/n) for the free overfalls with rough beds
Effect of Prismatic Sill on the Performance of Free Flow under Sluice Gate
2016-05
Journal of University of Zakho (Issue : 1) (Volume : 4)
Sills under sluice gates is used in hydraulic structures; their effect on the head generated upstream
gates for certain rate of flow is related to the height and length of sill. A study is held in laboratory flume
on four different prismatic sill heights and one model without sill by changing the gate opening four times
for each model. Statistical analyses on the dimensionless physical quantities are done. A positive effect of
sill on the performance of flow is noted by increasing the flow rate up to 25% for some models. The
coefficient of discharge decreases with increase of relative sill height to the head upstream and increases
with three other dimensionless parameters. The relative sill height to the gate opening shows the highest
correlation factor with the discharge coefficient and its positive effect on the flow phenomena is 55.4%.
Within the experimental measures limitations, a linear equation for predicting the discharge coefficient is
proposed with Adj. R2 0.923 .
Effect of Bed Slope on Flow Measurements in Trapezoidal Free Overfall Channels
2016-04
Arabian Journal for Science and Engineering (Issue : 10) (Volume : 41)
The aim of the present investigation is to studythe effect of both side and bed slopes on the flow over freeoverfalls in trapezoidal channels, three models of trapezoidal
free overfall channels have been built and tested in a laboοΏΎratory flume. These models had 0.1 m bed width and 3.7 mlength with different values of side slope (m = 0.268, 0.577,
and 1). Each model had four different bed slopes (S =0, 0.0033, 0.01, and 0.02). A total of twelve series of the experiments were tested for different ranges of Froude number.Experimental results of all models showed that the variation of (Qm1.5/gb5) with (myb/b) for different values of side slope and different bed slopes is a simple power equation.It was observed that the values of (Qm1.5/gb5) increase with the increase in (myb/b) values. The correlation between(myb/b) with (myc/b) is found to be linear for different bed slopes. The ratio (yb/yc) decreases with the increase of slope(S) with an average value of 0.729 for subcritical and superοΏΎcritical flow on smooth beds of different slopes. An empirical expression is obtained for the variation of (Qm1.5/ gb5) with (myb/b), and (S). The results of the present study have been compared with theoretical and experimental results obοΏΎtained by other investigators showing well agreements.
2015
Surface Roughness Effect on Discharge Coefficient of Combined Cylindrical Weir Gate Structure
2015-05
University of Zakho (Issue : 1) (Volume : 3)
The aim of this research is to investigate the effect of surface roughness on the performance of weir and
gate. An experimental study in a laboratory flume is carried out to study flow over and under cylindrical
weir gate in combined structure as flow measurement device. Four models having different diameters were
tested in a laboratory flume. In each model, the surface was roughed four times. The results of the test show
logical negative effect of the increase of surface roughness on the performance. The performance of the
combined structure improved with decrease ratio of roughness to the upstream head (Ks/H) and with the
increase of the total head to the diameter of the weir (H/d). Empirical relations were obtained to estimate
the variation of discharge coefficient (Cd) in terms of some dimensionless parameters. Within the limitations
of the present experimental work an equation to predict the discharge is proposed with R2 of 0.936. Finely
the contribution of the gate increases relative to the weir when the surface roughness increases.
2014
Surface Roughness Effects on Discharge Coefficient of Broad Crested Weir
2014-06
Research Journal of Applied Sciences, Engineering and Technology (Issue : 24) (Volume : 7)
The aim of this study is to investigate the effects of surface roughness sizes on the discharge coefficient
for a broad crested weirs. For this purpose, three models having different lengths of broad crested weirs were tested
in a horizontal flume. In each model, the surface was roughed four times. Experimental results of all models showed
that the logical negative effect of roughness increased on the discharge (Q) for different values of length. The
performance of broad crested weir improved with decrease ratio of roughness to the weir height (Ks/P) and with the
increase of the total Head to the Length (H/L). An empirical equation was obtained to estimate the variation of
discharge coefficient Cd in terms total head to length ratio, with total head to roughness ratio.
Back