3D Numerical Modeling of Flow and Sediment Transport in Open Channels |
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Authors: | Weiming Wu Wolfgang Rodi Thomas Wenka |
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Affiliation: | 11Visiting Scientist, Inst. for Hydromech., Univ. of Karlsruhe, Germany.
22Prof., Inst. for Hydromech., Univ. of Karlsruhe, Germany.
33Sr. Res. Engr., Fed. Wtrwy. Engrg. and Res. Inst., Karlsruhe, Germany.
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Abstract: | A 3D numerical model for calculating flow and sediment transport in open channels is presented. The flow is calculated by solving the full Reynolds-averaged Navier-Stokes equations with the k ? ε turbulence model. Special free-surface and roughness treatments are introduced for open-channel flow; in particular the water level is determined from a 2D Poisson equation derived from 2D depth-averaged momentum equations. Suspended-load transport is simulated through the general convection-diffusion equation with an empirical settling-velocity term. This equation and the flow equations are solved numerically with a finite-volume method on an adaptive, nonstaggered grid. Bed-load transport is simulated with a nonequilibrium method and the bed deformation is obtained from an overall mass-balance equation. The suspended-load model is tested for channel flow situations with net entrainment from a loose bed and with net deposition, and the full 3D total-load model is validated by calculating the flow and sediment transport in a 180° channel bend with movable bed. In all cases, the agreement with measurements is generally good. |
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