Effect of bed dunes on spatial development of open-channel flow
| Autor: | Alexander C. Demetracopoulos, Nikolaos Th. Fourniotis, Andreas P. Vouros, Athanassios A. Dimas |
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| Rok vydání: | 2008 |
| Předmět: |
Hydrology
Drag coefficient Condensed Matter::Other Turbulence Flow (psychology) Mechanics Physics::Geophysics Open-channel flow Condensed Matter::Soft Condensed Matter Physics::Fluid Dynamics Flow separation Drag Turbulence kinetic energy Reynolds-averaged Navier–Stokes equations Nonlinear Sciences::Pattern Formation and Solitons Geology Water Science and Technology Civil and Structural Engineering |
| Zdroj: | Journal of Hydraulic Research. 46:802-813 |
| ISSN: | 1814-2079 0022-1686 |
| Popis: | The spatial development of turbulent, sub-critical open-channel flow over five identical dunes is studied by the numerical solution of the RANS equations utilizing theVOF free-surface formulation and the k–e or Spalart–Allmaras turbulence models. Results are presented for smooth and rough walls and several dune dimensions. One of the cases was also studied experimentally. The flow separation at each dune crest generates a recirculation in the dune lee-side and reattachment at a distance, which increases with increasing dune height and decreasing dune length. Turbulence does not fully develop over the dunes, while the majority of turbulent kinetic energy production takes place in the recirculation region. The spatially mean, free-surface level decreases in the flow direction over the dunes, while the free-surface amplitude increases with increasing dune height. The dune drag coefficient increases with increasing dune height, while the contribution of form resistance on the drag increases with increasing du... |
| Databáze: | OpenAIRE |
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