## Published Journal Articles

##### 2023

### An Experimental Study of a Combined Oblique Cylindrical Weir and Gate Structure

2023-04

Engineering, Technology & Applied Science Research (Issue : 2) (Volume : 13)

In the present study, the effects of different oblique angles and diameters on the cylindrical weir and below
a gate as a combined device have been studied experimentally. For this purpose, sixteen models of
combined cylindrical weir-gate structures have been tested in a laboratory flume. These models had four
different oblique angles Ξ± (300, 450, 600, and 900). For each angle, the diameter of cylindrical weir-gate
changed four times (4, 7.3, 9, and 11cm). The results of all models indicate that the theoretical discharge
(Qth) is inversely proportional to the ratio of diameter to height (D/h) and length to height (L/h). As the
diameter increases and oblique angles decrease, the actual discharge (Qact) increases. A general expression
was established linking Qth/g1/2h5/2 and the discharge coefficient Cd with D/h, L/h, and alfa. The discharge
coefficient ranged from 0.55 to 0.99 for various oblique angles and decreased as the angle increased. A
strong correlation was observed between the estimated and the calculated values.

##### 2022

### Mathematical Model for Predicting the Development of Two-Phase Flow in a Horizontal Pipe

2022-10

Revista de Chimie (Rev. Chim.) (Issue : 4) (Volume : 73)

Prediction of the flow pattern is a central problms in multi-phase flow analysis. It is a vital point for researchers to accurately predict which flow pattern category types will occur at different flow rates. For this purpose, a mathematical model using the MATLAB (R2017b) computer program is developed for the prediction of gas-liquid two-phase flow patterns in a horizontal pipe with an inner diameter of 30mm under standard conditions. The properties of the air-water two-phase, the pipe geometry, and the flow rates of phases are defined to initiate the operating conditions. The mass flow rates of air and water changed from 0.002 to 0.004 kg/s and 0.672 to 1.334 kg/s, respectively. The impact of properties of the fluid and pipe diameters on two-phase flow configuration is considered to predict the impact of fluid properties on the flow pattern. The findings indicate that as the mass flux increases, the pipe diameters decrease, affecting the configuration of the flow pattern types. The mathematical modelβs predicted results are validated by comparing with previous studies. In addition, good agreement is obtained when the predicted results are compared to the ongoing experiment of this research.

### Pressure Drop in Horizontal Two-Phase Flow

2022-08

Engineering, Technology & Applied Science Reserch (Issue : 4) (Volume : 12)

In an artificial environment, the most important key in the process equipment design is determining gas-liquid two-phase flow frictional pressure drop of pipes. To achieve this, an experimental investigation was carried out in this study to analyze the pressure drops of air-water two-phase flow in a 30mm internal diameter horizontal pipe with a length of 6m at different flow conditions. The study was carried out at 20Co using tap water and air. To cover the slug flow pattern, the volumetric flow rate of water varied from 30 to 80 LPM, and the volumetric flow rate of air from 40 to 200 LPM. Pressure transmitters were used to measure pressure at four different points along the test section, each 2m apart. The results of the experiments were compared to 8 models using 3 distinct methods: Mean Absolute Percentage Error (MAPE), Relative Performance Factor (RPF), and the percentage of data included in the range of the 30% error band. All methods produced similar results, with the Sun-Mishima model being the most accurate.

##### 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.

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