Experimental and Numerical Investigation of Bed-Load Transport under Unsteady Flows
Publication: Journal of Hydraulic Engineering
Volume 137, Issue 10
Abstract
The dynamic behavior of bed-load sediment transport under unsteady flow conditions is experimentally and numerically investigated. A series of experiments are conducted in a rectangular flume (18 m in length, 0.80 m in width) with various triangular and trapezoidal shaped hydrographs. The flume bed of 8 cm in height consists of scraped uniform small gravel of . Analysis of the experimental results showed that bed-load transport rates followed the temporal variation of the triangular and trapezoidal hydrographs with a time lag on the average of 11 and 30 s, respectively. The experimental data were also qualitatively investigated employing the unsteady-flow parameter and total flow work index. The analysis results revealed that total yield increased exponentially with the total flow work. An original expression which is based on the net acceleration concept was proposed for the unsteadiness parameter. Analysis of the results then revealed that the total yield increased exponentially with the increase in the value of the proposed unsteadiness parameter. Further analysis of the experimental results revealed that total flow work has an inverse exponential variation relation with the lag time. A one-dimensional numerical model that employs the governing equations for the conservation of mass for water and sediment and the momentum was also developed to simulate the experimental results. The momentum equation was approximated by the diffusion wave approach, and the kinematic wave theory approach was employed to relate the bed sediment flux to the sediment concentration. The model successfully simulated measured sedimentographs. It predicted sediment yield, on the average, with errors of 7% and 15% of peak loads for the triangular and trapezoidal hydrograph experiments, respectively.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
This study was funded by research grants from TUBITAK through the Project No: UNSPECIFIED106M274. We also would like to express gratitude to Prof. Dr. Turhan Acatay for his support and guidance during both the planning and execution of the experiments. Finally, we would like to thank graduate student Erdi Aydöner and technician Isa Üstündağ for their help during the execution of the experiments.
References
Armanini, A., and di Silvio, G. (1988). “A one-dimensional model for the transport of a sediment mixture in nonequilibrium conditions.” J. Hydraul. Res., 26(3), 275–292.
Bor, A. (2008). “Numerical modeling of unsteady and nonequilibrium sediment transport in rivers.” M.Sc. thesis, Dept. of Civil Engineering, Izmir Inst. of Technology, Urla, Izmir.
Chien, N., and Wan, Z. H. (1999). Mechanics of sediment transport, ASCE, Reston. Va.
Cui, Y., Parker, G., Lisle, T. E., Pizzuto, J. E., and Dodd, A. M. (2005). “More on the evolution of bed material waves in alluvial rivers.” Earth Surf. Processes Landforms, 30, 107–114.
De Sutter, R., Verhoeven, R., and Krein, A. (2001). “Simulation of sediment transport during flood events: Laboratory work and field experiments.” Hydrol. Sci. J., 46(4), 599–610.
Graf, W. H. (2003). Fluvial hydraulics: Flow and transport processes in channels of simple geometry, Wiley, New York.
Graf, W. H., and Suszka, L. (1985). “Unsteady flow and its effect on sediment transport.” Proc., 21st IAHR Congr., Melbourne, Australia, Int. Assoc. for Hydro-Environment Eng. and Res., 540–544.
Hassan, M. A., Egozi, R., and Parker, G. (2006). “Experiments on the effect of hydrograph characteristics on vertical grain sorting in gravel bed rivers.” Water Resour. Res., 42(9), 1–15.
Kuhnle, R. A. (1992). “Bed-load transport during rising and falling stages on two small streams.” Earth Surf. Processes Landforms, 17(2), 191–197.
Lee, K. T., Liu, Y. L., and Cheng, K. H. (2004). “Experimental investigation of bed-load transport processes under unsteady flow conditions.” Hydrol. Processes, 18(13), 2439–2454.
Lindeburg, M. R. (1992). Engineer in training reference manual, 8th Ed., Professional Publications, Belmont, CA.
Plate, E. J. (1994). “The need to consider nonstationary sediment transport.” Int. J. Sediment Res., 9, 117–123.
Qu, Z. (2002). “Unsteady open-channel flow over a mobile bed.” Ph.D. thesis, No. 2688, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
Reid, I., L. Frostick, E., and Layman, J. T. (1985). “The incidence and nature of bed-load transport during flood flows in coarse-grained alluvial channels.” Earth Surf. Processes Landforms, 10(1), 33–44.
Singh, V. P., and Tayfur, G. (2008). “Kinematic wave theory for transient bed sediment waves in alluvial rivers.” J. Hydrol. Eng., 13(5), 297–304.
Singh, A. K., Kothyari, U. C., and Raju, K. G. R. (2004). “Rapidly varying transient flows in alluvial rivers.” J. Hydraul. Res., 42(5), 473–486.
Song, T., and Graf, W. H. (1997). “Experimental study of bed-load transport in unsteady open-channel flow.” Int. J. Sediment Res., 12,63–71.
Soni, J. P. (1981). “Laboratory study of aggradation in alluvial channels.” J. Hydrol. (Amsterdam),49(1–2), 87–106.
Tayfur, G., and Singh, V. P. (2006). “Kinematic wave model of bed profiles in alluvial channels.” Water Resour. Res., 42, W06414–W06426.
Tayfur, G., and Singh, V. P. (2007). “Kinematic wave model for transient bed profiles in alluvial channels under nonequilibrium conditions.” Water Resour. Res., 43, W12412–W12422.
Yang, C. T. (1996). Sediment transport: Theory and practice, McGraw-Hill, New York.
Yen, C. L., and Lee, K. T. (1995). “Bed topography and sediment sorting in channel bend with unsteady flow.” J. Hydraul. Eng., 121(8), 591–599.
Yen, C. L., Chang, S. Y., and Lee, H. Y. (1992). “Aggradation degradation process in alluvial channels.” J. Hydraul. Eng., 118(12), 1651–1669.
Wang, Z. (1994). “An experimental study of motion and deposition of gold particles in a mountain river.” J. Hydraul. Res., 32(5), 643–648.
Wilcock, P. R. (2001). “Toward a practical method for estimating sediment-transport rates in gravelbed rivers.” Earth Surf. Processes Landforms, 26(13), 1395–1408.
Wu, W., and Wang, S. S. Y. (2004). “Depth-averaged 2-D numerical modeling of unsteady flow and nonuniform sediment transport in open channels.” J. Hydraul. Eng., 130(10), 1013–1024.
Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 137 • Issue 10 • October 2011
Pages: 1276 - 1282
Copyright
© 2011 American Society of Civil Engineers.
History
Received: Dec 28, 2009
Accepted: Feb 23, 2011
Published online: Feb 25, 2011
Published in print: Oct 1, 2011
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.