Sediment transport by coherent structures in a turbulent open channel flow experiment
- 1.3k Downloads
In order to obtain more insight into the vertical transport of suspended sediment, an experiment was performed using a combination of PIV and PTV for the measurement of the fluid and particle velocity respectively. In this experiment, the particles were fed to the flow at 16 and 75 water depths from the measurement section with an injector located at the centerline of the channel near the free surface. At 16 water depths from the sediment injection, most sediment is still near the free surface, and the sediment is transported downwards in sweeps, thus leading to a mean particle velocity that is faster than the mean fluid velocity. It appears that in this situation, downward going particles are indeed found in sweeps (Q4), whereas upward going particles are preferentially concentrated in both Q1 and Q2 events. In the fully developed situation on the other hand, upward going particles are preferentially concentrated in ejections, while downward going ones are found in both Q3 and Q4 events, with a relatively increased frequency in Q3, and a decreased one in Q4. The increased number of particles in Q2 and Q3, which have low fluid velocities, leads to a mean particle velocity lower than the mean fluid velocity.
KeywordsParticle Image Velocimetry Particle Velocity Sediment Transport Coherent Structure Drift Velocity
Unable to display preview. Download preview PDF.
- G.K. Batchelor. An introduction to fluid dynamics. Cambridge university press, 1967.Google Scholar
- W.A. Breugem and W.S.J. Uijttewaal. A PIV/PTV experiment on sediment transport in a horizontal open channel flow. In R.M.L. Ferreira, E.C.L.T. Alves, J.G.A.B. Leal, and A.H. Cardoso, editors, River Flow, volume 1, pages 789–798. Taylor & Francis, 2006.Google Scholar
- LaVision. FlowMaster Manual. PIV Hardware Manual for Davis 6.2. Technical report, LaVision GmbH, February 2002.Google Scholar
- B. Mutlu Sumer and R. Deigaard. Particle motions near the bottom in turbulent flow in an open channel. part 2. Journal of Fluid Mechanics, 109:311–337, 1981.Google Scholar
- L.M. Portela. Indentification and characterization of vortices in the turbulent boundary layer. PhD thesis, Stanford University, 1997.Google Scholar
- G.A.J. van der Plas, M.L. Zoeteweij, R.J.M. Bastiaans, R.N. Kieft, and C.C.M. Rindt. PIV, PTV and HPV User’s Guide 1.1. Eindhoven University of Technology, April 2003. Draft.Google Scholar