Modeling Flow in an Open Channel with Heterogeneous Bed Roughness
Publication: Journal of Hydraulic Engineering
Volume 139, Issue 2
Abstract
Physical and numerical simulations of open channel flow over a heterogeneously roughened bed are examined. The velocity field is mapped at four different cross sections by using an acoustic Doppler velocimeter and the boundary shear stress obtained from both the velocity data and application of a Preston tube. These data illustrate that in the current arrangement the roughness elements dominate the physics of the flow and act as a source of vorticity, which is initially manifested as local boundary shear stress and, in turn, affects the secondary flow structures and momentum transfer in the channel. This paper presents the first attempt at using the Shiono–Knight method to model velocity and boundary shear stress distributions in a heterogeneous open channel. Appropriate advice concerning values of calibration parameters and discretization of the cross section is given. The combined physical/numerical approach provides an insight into the changing properties of the flow structure within a nonuniform roughness environment and will be of use to environmental regulators and river managers and academics working in the area.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
This research was funded by EPSRC DTA, for which the authors would like to express their gratitude. The authors would also like to thank Mr. M. Vanderstam of the University of Birmingham for his assistance in developing, building, and maintaining the equipment necessary for this research.
References
Ansari, K., Morvan, H. P., and Hargreaves, D. M. (2011). “Numerical investigation into secondary currents and wall shear in trapezoidal channels.” J. Hydraul. Eng., 137(4), 432–440.
Buffin-Belanger, T., and Roy, A. G. (2005). “1 min in the life of a river: Selecting the optimal record length for the measurement of turbulence in fluvial boundary layers.” Geomorph., 68(1–2), 77–94.
Chlebek, J. (2009). “Modelling of simple prismatic channels with varying roughness using the SKM and a study of flows in smooth non-prismatic channels with skewed floodplains.” Ph.D. thesis, Univ. of Birmingham, Birmingham, U.K.
Elder, J. W. (1959). “The dispersion of marked fluid in turbulent shear flow.” J. Fluid Mech., 5(4), 544–560.
Goring, D. G., and Nikora, V. I. (2002). “Despiking acoustic Doppler velocimeter data.” J. Hydraul. Eng., 128(1), 117–126.
Graf, W. H. (1991). “Flow resistance over a gravel bed: Its consequence on initial sediment movement.” Fluvial hydraulics of mountain regions: Lecture notes in earth sciences, Vol. 37, A. Armanini and G. Di Silvio, eds., Springer, Berlin, Heidelberg, 15–32.
Harvey, G. L., and Clifford, N. J. (2009). “Microscale hydrodynamics and coherent flow structures in rivers: Implications for the characterization of physical habitat.” River Res. Appl., 25(2), 160–180.
James, C. S., and Jordanova, A. A. (2010). “Reach-scale resistance of distributed roughness in channels.” River Flow 2010, A. Dittrich, K. Koll, J. Aberle, and P. Geisenhainer, eds., Bundesanstalt für Wasserbau (Federal Waterways Engineering and Research Institute), Karlsruhe, Germany, 333–341.
Jesson, M. (2012). “The effect of heterogeneous roughness on conveyance capacity and application to the Shiono-Knight method.” Ph.D. thesis, Univ. of Birmingham, Birmingham, U.K.
Jesson, M., Sterling, M., and Bridgeman, J. (2010). “Turbulent structures in heterogenous channels and their effects on converyance.” Proc., First IAHR European Div. Congress., International Association for Hydro-Environment Engineering and Research (IAHR), Madrid, Spain.
Jesson, M., Sterling, M., and Bridgeman, J. (2012). “An experimental study of turbulence in a heterogeneous channel.” Proc. Inst. Civ. Eng.: Water Manage, (Jul. 3, 2012).
Jowett, I. G. (1993). “A method for objectively identifying pool, run and riffle habitats from physical measurements.” N. Z. J. Mar. Freshwater Res., 27(2), 241–248.
Khodashenas, S. R., and Paquier, A. (1999). “A geometrical method for computing the distribution of boundary shear stress across irregular straight open channels.” J. Hydraul. Res., 37(3), 381–388.
Knight, D. W. (1981). “Boundary shear in smooth and rough channels.” J. Hydr. Div., 107(7), 839–851.
Knight, D. W., Omran, M., and Tang, X. (2007). “Modeling depth-averaged velocity and boundary shear in trapezoidal channels with secondary flows.” J. Hydraul. Eng., 133(1), 39–47.
Knight, D. W., and Sterling, M. (2000). “Boundary shear in circular pipes running partially full.” J. Hydraul. Eng., 126(4), 263–275.
McGahey, C., Samuels, P. G., and Knight, D. W. (2006). “A practical approach to estimating the flow capacity of rivers—Application and analysis.” River Flow 2006, R. M. L. Ferreira, E. C. T. L. Alves, J. G. A. B. Leal, and A. H. Cardoso, eds., Taylor and Francis, London, 303–312.
Mclelland, S. J., Ashworth, P. J., Best, J. L., and Livesey, J. R. (1999). “Turbulence and secondary flow over sediment stripes in weakly bimodal bed material.” J. Hydraul. Eng., 125(5), 463–473.
Nezu, I., and Nakagawa, H. (1993). Turbulence in open-channel flows, Balkema, Rotterdam, Netherlands.
Omran, M. (2005). “Modelling stage-discharge curves, velocity and boundary shear stress distributions in natural and artificial channels using a depth-averaged approach.” Ph.D. thesis, Univ. of Birmingham, Birmingham, U.K.
Omran, M., and Knight, D. W. (2006). “Modelling the distribution of boundary shear stress in open channel flows.” River Flow 2006, R. M. L. Ferreira, E. C. T. L. Alves, J. G. A. B. Leal, and A. H. Cardoso, eds., Taylor and Francis, London, 397–404.
Omran, M., and Knight, D. W. (2010). “Modelling secondary cells and sediment transport in rectangular channels.” J. Hydraul. Res., 48(2), 205–212.
Padmore, C. L. (1997). “Physical biotopes in representative river channels: Identification, hydraulic characterisation and application.” Ph.D. thesis, Newcastle Univ., Tyne and Wear, U.K.
Patel, V. C. (1965). “Calibration of the Preston tube and limitations on its use in pressure gradients.” J. Fluid Mech., 23(1), 185–208.
Perkins, H. J. (1970). “The formation of streamwise vorticity in turbulent flow.” J. Fluid Mech., 44(4), 721–740.
Shiono, K., and Knight, D. W. (1988). “Two dimensional analytical solution for a compound channel.” Proc., 3rd Int. Symp. on Refined Flow Modelling and Turbulence Measurements, Y. Iwasa, N. Tamai, and A. Wada, eds., Universal Academy Press, Tokyo, Japan, 503–510.
Shiono, K., and Knight, D. W. (1991). “Turbulent open-channel flows with variable depth across the channel.” J. Fluid Mech., 222, 617–646.
Sterling, M., Beaman, F., Morvan, H., and Wright, N. G. (2008). “Bed shear stress characteristics of a simple, prismatic, rectangular channel.” J. Eng. Mech., 134(12), 1085–1094.
Sterling, M., and Knight, D. W. (2000). “Resistance and boundary shear in circular conduits with flat beds running part full.” Proc. Inst. Civ. Eng.: Water Marit. Eng., 142(4), 229–240.
Studerus, F. X. (1982). Sekundärströmungen im offenen Gerinne über rauhen Längsstreifen, Dissertation ETH Nr. 7035, Eidgenössischen Technischen Hochschule, Zurich, Switzerland.
Tang, X., and Knight, D. W. (2008). “A general model of lateral depth-averaged velocity distributions for open channel flows.” Adv. Water Resour., 31(5), 846–857.
Tang, X., Sterling, M., and Knight, D. W. (2010). “A general analytical model for lateral velocity distributions in vegetated channels.” River Flow 2010, A. Dittrich, K. Koll, J. Aberle, and P. Geisenhainer, eds., Bundesanstalt für Wasserbau (Federal Waterways Engineering and Research Institute), Karlsruhe, Germany, 469–475.
Vermaas, D. A. (2008). Mixing layer phenomena in open channel flow with heterogeneous bed roughnesss, Wageningen Univ./Delft Univ. of Technology, Delft, Netherlands.
Vermaas, D. A., Uijttewaal, W. S. J., and Hoitink, A. J. F. (2011). “Lateral transfer of streamwise momentum caused by a roughness transition across a shallow channel.” Water Resour. Res., 47(2), W02530.
Wu, S., and Rajaratnam, N. (2000). “A simple method for measuring shear stress on rough boundaries.” J. Hydraul. Res., 38(5), 399–400.
Yang, S. Q., and Lim, S. Y. (1998). “Boundary shear stress distributions in smooth rectangular channels.” Proc. Inst. Civ. Eng., Water Marit. Eng., 130(3), 163–173.
Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 139 • Issue 2 • February 2013
Pages: 195 - 204
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Nov 27, 2011
Accepted: Jul 12, 2012
Published online: Nov 5, 2012
Published in print: Feb 1, 2013
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.