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

7th AIC‐ICMR on Sciences and Engineering 2017

自然科学;工业技术

Rizalihadi, M.^1 ; Ziana^1 ; Shaskia, Nina^1 ; Asharly, H.^1

Civil Engineering Department, University of Syiah Kuala, Jl. Syekh Abdurrauf No. 7, Darussalam, Banda Aceh, Indonesia^1

关键词: Channel roughness;    Manning coefficient;    Manning's coefficients;    Manning's equations;    Mean velocities;    Open channels;    Plant height;    Water profiles;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/352/1/012039/pdf
DOI  :  10.1088/1757-899X/352/1/012039

来源: IOP

【 摘 要 】

One of the important factors in channel dimension is the Manning's coefficient ( n ). This coefficient is influenced not only by the channel roughness but also by the presence of plants in the channel. The aim of the study is to see the effect of the ratio between the height of the rigid plant and water depth on the Manning's coefficient (n) in open channel. The study was conducted in open channel with 15.5 m long, 0.5 m wide and 1.0 m high, in which at the center of the channel is planted with the rigid plants with a density of 42 plants/m2. The flow was run with a discharge of 0.013 m3/s at 6 ratios of Hplants/Hwater, namely: 0; 0.2; 0.6; 0.8; 1,0 and 1,2, to obtain the velocity and water profiles. Then the value of n is analyzed using Manning's equation. The results showed that the mean velocity becomes decrease 17.81-34.01% as increase the ratio of Hplants/Hwater. This results in increasing n value to become 1.22-1.52 times compared to the unplanted channel ( no =0.038). So, it can be concluded that the ratio between the rigid plant's height and water depth in the open channel can affect the value of Manning coefficient.