Velocity and Concentration Fields in Uniform Flow with Coarse Sands
Publication: Journal of Hydraulic Engineering
Volume 125, Issue 6
Abstract
The vertical distributions of velocity and concentration for an open-channel flow mixed with coarse sands are investigated by using a mathematical model, taking account of the momentum transfer by the turbulent motion and the sediment mass balance by the diffusion and settling in a two-dimensional steady-state condition. An attempt is made here to obtain the horizontal time-mean velocity component and the sediment concentration quantitatively at a certain depth. An examination of measured velocity profiles plotted on semilogarithmic paper leads to the conclusion that the general characteristic of the flow is greatly affected by the increasing sediment load. The vertical distribution of the time-mean velocity is calculated by following the velocity gradient equation previously proposed. The concentration field is divided into the outer region and the inner region, since in each region the fall velocity varies according to the grain Reynolds number. For computing the concentration of suspended sediment, therefore, the writer proposes two formulas derived from Fick's diffusion equation. The theoretical results obtained by the velocity and concentration equations are found to be in good agreement with a set of experimental data, for the mean diameters of the sands ranged from 940 to 1,300 μm.
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References
1.
Bhattacharya, P. K. ( 1971). “Sediment suspension in shoaling waves,” PhD thesis, University of Iowa, Iowa City, Iowa.
2.
Coleman, N. L. (1969). “A new examination of sediment suspension in open channels.”J. Hydr. Res., Delft, The Netherlands, 7, 67–82.
3.
Coleman, N. L. (1981). “Velocity profiles with suspended sediment.”J. Hydr. Res., Delft, The Netherlands, 19(3), 211–229.
4.
Coles, D. ( 1956). “The law of the wake in the turbulent boundary layer.” J. Fluid Mech., 1, 191–226.
5.
Einstein, H. A., and Chien, N. ( 1955). “Effects of heavy sediment concentration near the bed on the velocity and sediment distribution.” Rep. No. 8, University of California, Berkeley, Calif.
6.
Hino, M. (1963). “Turbulent flow with suspended particles.”J. Hydr. Div., ASCE, 89(4), 161–185.
7.
Itakura, T., and Kishi, T. (1980). “Open channel flow with suspended sediments.”J. Hydr. Div., ASCE, 106(8), 1325–1343.
8.
Lau, Y. L. (1983). “Suspended sediment effect on flow residence.”J. Hydr. Div., ASCE, 109(5), 757–763.
9.
Murota, A. ( 1953). “On the relationship between the concentration of suspended sediment and the velocity distribution of water flow.” J. JSCE, Tokyo, 38(11), 8–10 (in Japanese).
10.
Prandtl, L. ( 1932). “Zur turbulenten Stömung in Röhren und längs Platten.” Egebn. Aerodyn. Versuchsanst, University of Göttingen, Germany, Ser. 4, 18–29 (in German).
11.
Richardson, J. F., and Zaki, W. N. ( 1954). “Sedimentation and fluidization—Part I.” Trans., Instn. of Chemical Engrs., 32, 35–53.
12.
Rouse, H. ( 1937). “Modern conceptions of the mechanics of fluid turbulence.” Trans., ASCE, Reston, Va., 102, 463–543.
13.
Tsubaki, T. ( 1955). “On the effects of suspended sediment on flow characteristics.” J. JSCE, Tokyo, 40(9), 1–6 (in Japanese).
14.
Umeyama, M. (1992). “Vertical distribution of suspended sediment in uniform open-channel flow.”J. Hydr. Engrg., ASCE, 118(6), 936–941.
15.
Umeyama, M., and Gerritsen, F. (1992). “Velocity distribution in uniform sediment-laden flow.”J. Hydr. Engrg., ASCE, 118(2), 229–245.
16.
Vanoni, V. A. ( 1946). “Transportation of suspended sediment by water.” Trans., ASCE, Reston, Va., 111, 67–133.
17.
van Rijn, L. C. ( 1987). “Mathematical modeling of morphological processes in the case of suspended sediment transport,” PhD thesis, Delft University of Technology, Delft, The Netherlands.
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Published online: Jun 1, 1999
Published in print: Jun 1999
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