Turbulence Structures in Flow over Two-Dimensional Dunes
Publication: Journal of Hydraulic Engineering
Volume 134, Issue 1
Abstract
This paper presents a large eddy simulation (LES) of turbulent open channel flow over two-dimensional periodic dunes. The Reynolds number based on the bulk velocity (bulk) and the maximum flow depth , is approximately 25,000. The instantaneous flow field is investigated with special emphasis on the occurrence of coherent structures. Instantaneous vortices were visualized and it is shown that separated vortices are formed downstream of the dune crest due to Kelvin–Helmholtz instabilities. Near the point of reattachment the so-called kolk-boil vortex evolves in form of a hairpin vortex. Also present are previously separated vortices, which are convected along the stoss side of the downstream dune and elevated toward the water surface. The existence of near wall streaks which reform shortly after reattachment is also shown. The spacing between two low-speed streaks is very similar to that observed previously over smooth and rough walls. For validation, profiles of the time-averaged velocities, streamwise, and wall-normal turbulent intensities and the Reynolds shear stress calculated by the LES are presented and compared with available laser Doppler velocimetry measurements and overall good agreement is found.
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Acknowledgments
This work is part of a research project funded by the German Research Foundation (DFG) under Project No. UNSPECIFIEDRo 558/29-1. The computations were carried out on the high performance computer IBM SP-SMP at the Scientific Supercomputing Centre (SSCK) at the University of Karlsruhe. Dr. Jan Wissink is thanked for his help with the generation of the high-quality grids. The provision of the experimental data by Ceyda Polatel of the Iowa Institute of Hydraulic Research (IIHR) is acknowledged.
References
de Angelis, V., Lombardi, P., and Banerjee, S. (1997). “Direct numerical simulation of turbulent flow over a wavy wall.” Phys. Fluids, 9, 2429–2442.
Armenio, V., and Piomelli, U. (2000). “Applications of a Lagrangian mixed model in generalize coordinates.” Flow, Turbul. Combust., 65, 51–81.
Best, J. L. (2005). “The fluid dynamics of river dunes: A review and some future research directions.” J. Geophys. Res., 110, 1.
Breuer, M., and Rodi, W. (1996). “Large eddy simulation of complex turbulent flows of practical interest.” Flow simulation with high performance computers II, E. Hirschel, ed., Notes on Numerical Fluid Mechanics Vol. 52, Vieweg, Braunschweig, Germany, 258–274.
Brooks, N. H. (1958). “Mechanics of streams with movable bed of fine sands.” Trans. Am. Soc. Civ. Eng., 123, 526–594.
Calhoun, R. J. (1998). “Numerical investigations of turbulent flow over complex terrain.” Ph.D. dissertation, Dept. of Civil & Environmental Engineering., Stanford Univ., Stanford, Calif.
Calhoun, R. J., and Street, R. L. (2001). “Turbulent flow over a wavy surface: Neutral case.” J. Geophys. Res., 106(C5), 9277–9294.
Coleman, S. E., and Melville, B. W. (1996). “Initiation of bed forms on a flat sand bed.” J. Hydraul. Eng., 122(6), 301–310.
Defina, A. (1996). “Transverse spacing of low-speed streaks in a channel flow over a rough bed.” Coherent flow structures in open channels, P. J. Ashworth et al., eds., Wiley, New York.
Engel, P. (1981). “Length of flow separation over dunes.” J. Hydr. Div., 107(10), 1133–1143.
Fröhlich, J., Mellen, C. P., Rodi, W., Temmerman, L., and Leschziner, M. A. (2005). “Highly-resolved large eddy simulation of separated flow in a channel with streamwise periodic constrictions.” J. Fluid Mech., 526, 19–66.
Germano, M., Piomelli, U., Moin, P., and Cabot, W. H. (1991). “A dynamic subgrid-scale eddy viscosity model.” Physics of Fluids, 3(7), 1760–1765.
Ghosal, S., Lund, T. S., Moin, P., and Akselvoll, K. (1995). “A dynamic localization model for large-eddy simulation of turbulent flows.” J. Fluid Mech., 286, 229–255.
Gilbert, G. K. (1914). “Transportation of debris by running water.” USGS Professional Paper No. 86, U.S. Ecological Survey, Washington, D.C.
Guy, H. P., Simons, D. B., and Richardson, E. V., (1963). “Summary of alluvial channel data from flume experiments, 1956-61.” USGS Professional Paper No. 96, U.S. Ecological Survey, Washington, D.C.
Hinterberger, C. (2004). “Dreidimensionale und tiefengemittelte large-eddy-simulation von Flach-wasserströmungen.” Ph.D. thesis, Univ. of Karlsruhe, Karlsruhe, Germany.
Hyun, B. S., Balachandar, R., Yu, K., and Patel, V. C. (2003). “Assessment of PIV to measure mean velocity and turbulence in water flow.” Exp. Fluids, 35, 262–267.
Jeong, J., and Hussain, F. (1995). “On the identification of a vortex.” J. Fluid Mech., 285, 69–94.
Johns, B., Soulsby, R. L., and Xing, J. (1993). “A comparison of numerical model experiments of free surface flow over topography with flume and field observations.” J. Hydraul. Res., 31(2), 215–228.
Kadota, A., and Nezu, I. (2002). “Three dimensional structure of spacer-time correlation on coherent vortices generated behind dune crest.” J. Hydraul. Res., 37(1), 59–80.
Leschziner, M. A., and Launder, B. E. (1993). 2nd ERCOFTAC-IAHR Workshop on Refined Flow Modelling, Univ. of Manchester Institute of Science and Technology, Manchester, U.K.
Lilly, D. K. (1992). “A proposed modification of the Germano subgrid-scale closure method.” Phys. Fluids, 4, 633–635.
López, F., Fernández, R., and Best, J. L. (2000). “Turbulence and coherent flow structures associated with bed form amalgamation: An experimental study of the ripple-dune transition.” Joint Conf. on Water Resource Engineering and Water Resources Planning and Management.
Lyn, D. A. (1993). “Turbulence measurements in open-channel flows over artificial bed forms.” J. Hydraul. Res., 119(3), 306–326.
Maddux, T. B., McLean, S. R., and Nelson, J. M. (2003a). “Turbulent flow over 3D dunes. II: Fluid and bed stresses.” J. Geophys. Res., 108 (Fl), Art. No F16010.
Maddux, T. B., Nelson, J. M., and McLean, S. R. (2003b). “Turbulent flow over 3D dunes. I: Free surface and flow response.” J. Geophys. Res., 108 (F1), Art. No F16009.
Marchioli, C., Armenio, V., Salvetti, M. V., and Soldati, A. (2006). “Mechanisms for deposition and resuspension of heavy particles in turbulent flow over wavy interfaces.” Phys. Fluids, 18, 025102–1.
McLean, S. M., Nelson, J. M., and Wolfe, S. R. (1993). “Turbulence structures over two-dimensional bed forms: Implications for sediment transport.” J. Geophys. Res., 99(C6), 12729–12747.
Mendoza, C., and Shen, H. (1990). “Investigation of turbulent flow over dunes.” J. Hydraul. Eng., 116(4), 459–477.
Mierlo, M. C. L. M., and de Ruiter, J. C. C. (1988). “Turbulence measurements above artificial dunes.” Rep. No. Q789, Delft Hydraulics Laboratory, Delft, The Netherlands.
Müller, A. (1987). “An experimental investigation of the mixing layer behind dunes with combined flow visualization and velocity measurement.” Turbulence measurements and plow modeling, Hemisphere, Wash., 229–238.
Müller, A., and Gyr, A. (1986). “On the vortex formation in the mixing layer behind dunes.” J. Hydraul. Res., 24(5), 359–375.
Nelson, J. M., and Smith, J. D. (1989). “Mechanics of flow over ripples and dunes.” J. Geophys. Res., 94(C6), 8146–8162.
Nezu, I., and Nakagawa, H. (1993a). “Three-dimensional structures of coherent vortices generated behind dunes in turbulent free-surface flows. Refined flows modelling and turbulence measurements.” Proc. 5th Int. Symp., Paris, 603–612.
Nezu, I., and Nakagawa, H. (1993b). “Turbulence in open channel flows.” IAHR monograph, Balkema, Rotterdam, The Netherlands.
Patel, V. C., and Lin, C. L. (2004). “Turbulence modeling in flow over a dune with special reference to free surface and bed roughness effects.” Proc., 6th Int. Conf. on Hydroscience and Engineering (ICHE-2004), Brisbane, Australia.
Perić, M., Ruger, M. and Scheuerer, G. (1988). “Calculation of the two-dimensional turbulent flow over a sand dune model.” Rep. No. SRR-TN-88-02, Univ. of Erlangen, Erlangen, Germany.
Perot, B., and Moin, P. (1995). “Shear-free turbulent boundary layers. 1: Physical insights into near-wall turbulence.” J. Fluid Mech., 295, 199–227.
Piomelli, U., and Chasnov, J. R. (1996). “Large-eddy simulations: Theory and applications.” Transition and turbulence modelling, Henningson, Hallback, Alfredsson Johansson, eds., Kluwer Academic, Dordrecht, The Netherlands.
Polatel, C. (2006). “Large-scale roughness effect on free-surface and bulk flow characteristics in open-channel flows.” Ph.D. thesis, Iowa Institute of Hydraulic Research, The Univ. of Iowa, Ames, Iowa.
Salvetti, M. V., Damiani, R., and Beux, F. (2001). “Three-dimensional coarse large-eddy simulations of the flow above two-dimensional sinusoidal waves.” Int. J. Numer. Methods Fluids, 35(6), 617–642.
Simons, D. B., and Richardson, E. V. (1963). “Forms of bed roughness in alluvial channels.” Trans. Am. Soc. Civ. Eng., 128(1). 284–302.
Smagorinsky, J. (1963). “General circulation experiments with the primitive equation. I: The basic experiment.” Mon. Weather Rev., 91, 99–152.
Smith, C. R., and Metzler, S. P. (1983). “The characteristics of low-speed streaks in the near-wall region of a turbulent boundary layer.” J. Fluid Mech., 129, 27–54.
Sukhodolov, A. N., Fedele, J. J., and Rhoads, B. L. (2006). “Structure of flow over alluvial bed forms: An experiment on linking field and laboratory methods.” Earth Surf. Processes Landforms, 31, 1292–1310.
Temmerman, L. (2004). “Large eddy simulation of separating flow from curved surfaces.” Ph.D. thesis, Dept. of Engineering, Queen Mary and Westfield Univ. of London, Univ. of London, London.
Yoon, J. Y., and Patel, V. C. (1996). “Numerical model of turbulent flow over sand dune.” J. Hydraul. Eng., 122, 10–18.
Yue, W., Lin, C. L., and Patel, V. C. (2005a). “Coherent structures in open channel flows over a fixed dune.” J. Fluids Eng., 127(5), 858–864.
Yue, W., Lin, C. L., and Patel, V. C. (2005b). “Large eddy simulation of turbulent open-channel flow with free surface simulated by level set method.” Phys. Fluids, 17(2), 025108.
Yue, W., Lin, C. L., and Patel, V. C. (2006). “Large-eddy simulation of turbulent flow over a fixed two-dimensional dune.” J. Hydraul. Eng., 132(7), 643–651.
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Published In
Journal of Hydraulic Engineering
Volume 134 • Issue 1 • January 2008
Pages: 42 - 55
Copyright
© 2008 ASCE.
History
Received: Oct 17, 2006
Accepted: Jul 20, 2007
Published online: Jan 1, 2008
Published in print: Jan 2008
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