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| Titel |
Mitigation of turbidity currents in reservoirs with passive retention systems: validation of CFD modeling |
| VerfasserIn |
E. Ferreira, E. Alves, R. M. L. Ferreira |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250068843
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| Zusammenfassung |
| Sediment deposition by continuous turbidity currents may affect eco-environmental river
dynamics in natural reservoirs and hinder the maneuverability of bottom discharge gates in
dam reservoirs. In recent years, innovative techniques have been proposed to enforce the
deposition of turbidity further upstream in the reservoir (and away from the dam), namely, the
use of solid and permeable obstacles such as water jet screens , geotextile screens,
etc..
The main objective of this study is to validate a computational fluid dynamics (CFD) code
applied to the simulation of the interaction between a turbidity current and a passive retention
system, designed to induce sediment deposition.
To accomplish the proposed objective, laboratory tests were conducted where a simple
obstacle configuration was subjected to the passage of currents with different initial sediment
concentrations.
The experimental data was used to build benchmark cases to validate the 3D CFD
software ANSYS-CFX. Sensitivity tests of mesh design, turbulence models and discretization
requirements were performed.
The validation consisted in comparing experimental and numerical results, involving
instantaneous and time-averaged sediment concentrations and velocities. In general, a good
agreement between the numerical and the experimental values is achieved when: i) realistic
outlet conditions are specified, ii) channel roughness is properly calibrated, iii) two
equation k - É models are employed iv) a fine mesh is employed near the bottom
boundary.
Acknowledgements
This study was funded by the Portuguese Foundation for Science and Technology through
the project PTDC/ECM/099485/2008. The first author thanks the assistance of Professor
Moitinho de Almeida from ICIST and to all members of the project and of the Fluvial
Hydraulics group of CEHIDRO. |
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