Velocity Distribution Inside and Above Branched Flexible Roughness
Publication: Journal of Irrigation and Drainage Engineering
Volume 118, Issue 6
Abstract
The purpose of this study is to develop function relationships for the velocity distribution of water flow in and above a model of branched grass. A trapezoidal cross‐section flume is constructed for this study, and branched plastic strips are used to simulate the grass in nature. A correct determination of flow characteristics for channels suffering from submerged weeds is desirable. Furthermore, knowledge of the changes of velocity distribution as a result of the presence of weeds and the changes in the shear stress at the bed will improve understanding of the different problems associated with this type of channel. Power‐ and logarithmic‐function relationships are developed to describe the velocity distribution of water inside and above branched flexible‐roughness elements (which represent the submerged weeds) in trapezoidal open channels. An experimental study was carried out in the hydraulic lab at Cairo University, Cairo, Egypt, to check the validity of the prediction equations that relate the velocity distribution to the depth of water in the channel cross section. More than 170 velocity profiles have been measured at different locations along the channel length and its cross sections.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Elgamal, F. H. (1990). “Effect of flexible roughness (weeds) on flow in trapezoidal open channels,” MSc thesis, Cairo University, Giza, Egypt.
2.
Fenzl, R. N. (1962). “Hydraulic resistance of broad shallow vegetated channels,” PhD dissertation, University of California, Davis, Calif.
3.
Gourlay, M. R. (1970). Discussion of “Flow retardance in vegetated channels” by N. Kouwen, T. E. Unnay, and H. M. Hill. J. Irrig. and Drain. Div., ASCE, 96(3), 351–357.
4.
Kouwen, N., and Unnay, T. E. (1973). “Flexible roughness in open channels.” J. Hydr. Div., ASCE, 99(5), 713–728.
5.
Kouwen, N., Unnay, T. E., and Hill, H. M. (1969). “Flow retardance in vegetated channels.” J. Irrig. and Drain. Div., ASCE, 95(2), 329–342.
6.
Phelps, H. O. (1970). “The friction coefficient for shallow flows over a simulated turf surface.” Water Resour. Res., 6(4), 1220–1226.
7.
Plate, E. J., and Quraishi, A. A. (1965). “Modeling velocity distribution inside and above tall crops.” J. Appl. Meterorology, 4(3), 400–408.
8.
Quraishi, A. A. (1963). “Effect of flexible roughness elements on diffusion in a turbulent boundary layer,” PhD dissertation, Colorado State University, Fort Collins, Colo.
9.
Quraishi, A. A., and Abou‐Seida, M. M. (1975). “Velocity distribution inside and above flexible roughness.” Research Report No. AM‐1/96, Riyadh Univ., Riyadh, Saudi Arabia.
10.
Ree, W. O., and Palmer, V. J. (1949). “Flow of water in channels protected by vegetative linings.” U.S. Soil Conservation Bulletin No. 967, U.S. Superintendent of Documents, Washington, D.C., Feb., 115.
11.
Temple, D. M. (1986). “Velocity distribution coefficients for grass‐lined channels.” J. Hydr. Engrg. Div., ASCE, 112(3), 193–205.
Information & Authors
Information
Published In
Journal of Irrigation and Drainage Engineering
Volume 118 • Issue 6 • November 1992
Pages: 914 - 927
Copyright
Copyright © 1992 ASCE.
History
Published online: Nov 1, 1992
Published in print: Nov 1992
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.