The effect of ratio between rigid plant height and water depth on the manning’s coefficient in open channel

Rizalihadi, Maimun; Ziana,; Shaskia, Nina; Asharly, H

doi:10.1088/1757-899x/352/1/012039

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…The procedure of research method which is applied in this research is the same as and follows the previous research done by [6][7][8][9]. The difference is only on placing vegetation treatments and method of data analysis.…”

Section: Experimental Designs and Methodsmentioning

confidence: 99%

The effect of density and height of vegetation in open channel on the Manning’s coefficient

Rizalihadi

2019

MATEC Web Conf.

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One of an important parameter to study water flow in channel is Manning’s coefficient (n). This coefficient is produced not only from material forming the channel, but also due to presence of vegetation in channel. The aim of research is to study the effect of vegetation density and height on Coefficient of Manning in open channel. The study was conducted in open channel with 15.5 m long, 0.5 m wide and 1.0 m high. At the center of 3 m long of channel is planted with Sweet flag (Acorus calamus). The impact of various densities and heights of sweet flag were examined using fixed discharge to measure velocity and slope energy. Coefficient of Manning was obtained using Manning’s equation. Statistical analysis of variance with significance level of 0.05 was adopted to evaluate the effect of variables. The result showed that increasing density and height of Sweet flag make decreasing velocity and increasing Coefficient of Manning to be 0,043-0,064, or 1.40-2.10 times compared to un-vegetated channel (no=0.031). Based on statistical analysis, it is found that Fcalc=15.646 and 16.928 for vegetation density and height respectively, which is larger than FStat=2,603. It can be concluded that density and height of vegetation significantly influence on Coefficient of Manning.

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Section: Experimental Designs and Methodsmentioning

confidence: 99%

The effect of density and height of vegetation in open channel on the Manning’s coefficient

Rizalihadi

2019

MATEC Web Conf.

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“…Fig. 24 Relationship between the calculated relative specific energy (E rc ) and predicted relative specific energy (E rp ) for the un-grassed canal…”

Section: Gep Spssmentioning

confidence: 99%

“…However, the GEP model, which produced a physical equation that is applicable in engineering practice, would be preferred. Rizalihadi et al [24] studied the effect of the ratio between the height of the rigid plant and water depth on Manning's coefficient (n) in an open channel. The results showed that the mean velocity becomes decreases 17.81-34.01% as increase the ratio of Hplants/Hwater.…”

Section: Introductionmentioning

confidence: 99%

Assessment of flow characteristics through a grassed canal

Gad¹,

Sobeih

Rashwan

et al. 2021

Innov. Infrastruct. Solut.

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Vegetation is defined as a kind of surface roughness, which reduces the capacity of the channel and retards the flow by causing loss of energy through turbulence and drag forces of moving water. In water channels, vegetation maybe used to stabilize the water surface and prevent erosion caused by concentrated water flow. In terms of channel lining, grass offers the least expensive option and is the most esthetically pleasing. Most previous studies on this subject were conducted using artificial vegetation in laboratory experiments; research conducted in canals with natural vegetation is lacking. In this study, flow characteristics through a natural grassed canal are studied. In addition, the Manning coefficient and specific energy were determined based on field measurements for both grassed and un-grassed canals. The fieldwork was conducted on Ganabia 9B, southeast of El-Mahalla El Kubra, El-Gharbia, Egypt. The average heights of vegetation in the grassed canal ranged from (28 to 100) cm and the values of flow rate range from (0.0504 to 0.1127) m 3 /s. The number of tests is 42 tests for the un-grassed canal and 205 tests for the grassed canal. This study indicated that the Manning coefficient increased with an increase in energy and momentum coefficients. The energy coefficient increased with a decrease in relative specific energy and an increase in grass height. The un-grassed canal exhibited a smaller relative specific energy than the grassed canal. The momentum coefficients for the non-grassed and grassed canals were 1.015-1.517 and 1.003-1.655, respectively. Therefore, the un-grassed canal showed a higher momentum coefficient than the grassed canal at a ratio of 0.264-1.196%. The relative specific energy was calculated in two ways: (i) using the actual energy coefficient values and (ii) setting it equal to one. As such, the error percentages of the specific energy for the grassed and un-grassed canals were 0.000105-0.1652% and 0.0048-0.2194%, respectively. The results obtained herein were compared with those obtained in previous studies, showing good agreement, but differ in the accuracy of predicting values. Three programs, i.e., gene expression programming, Statistical Package for the Social Sciences, and artificial neural network, were employed to create empirical formulas for modeling the Manning coefficient and relative specific energy for the grassed and un-grassed canals. Gene expression programming was found to be the best modeling program.

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Numerical modeling of a liquid-gas interface flow in a channel

Silva

Chinchilla

Fossi

et al. 2019

J. Phys.: Conf. Ser.

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Water forms open channels, whether natural or artificial, which are studied in phenomena as in a flood; in order to save the greatest number of important people; important variables are the velocity profile and the pressure. The estimation of these variables is proposed using numerical model which is solved for the separate phases of liquid and gas using the Navier Stokes equation and for the liquid-gas interface the volume of fluid method is proposed, with two elements are estimated in a global way (liquid-gas) as if there were only one component. The equations are solved using the finite volume method. In addition, a mesh analysis is performed according to the channel geometry; the mesh types are hexahedral and tetrahedral with a number of elements respectively of 16791 and 166500. The tests carried out show a wave phenomenon in which the velocity of the flow increases from 0.7 m/s to 2.12 m/s and from 0.05 m to 0.07 m in height. In addition, an oscillatory movement was discovered which generated pressure gradients that varied between 0.2 kPa to 0.5 kPa. Tests are also carried out with other types of channels in which dry zones are observed, which are redesigned to reduce costs.

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The effect of ratio between rigid plant height and water depth on the manning’s coefficient in open channel

Cited by 4 publications

References 6 publications

The effect of density and height of vegetation in open channel on the Manning’s coefficient

The effect of density and height of vegetation in open channel on the Manning’s coefficient

Assessment of flow characteristics through a grassed canal

Numerical modeling of a liquid-gas interface flow in a channel

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