IAHR, founded in 1935, is a worldwide independent member-based organisation of engineers and water specialists working in fields related to the hydro-environmental sciences and their practical application. Activities range from river and maritime hydraulics to water resources development and eco-hydraulics, through to ice engineering, hydroinformatics, and hydraulic machinery.
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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Hydro-environment : Flow fields around fish guidance structures
Flow fields around fish guidance structures
Downstream fish passage through turbines or over spillways may significantly increase fish mortality during migration periods. Therefore the implementation of protection systems stopping fish from entering turbine intakes has a high priority in regard to ecologically upgrading hydro power plants (HPPs). For that reason VAW of ETH Zurich conducts research on louvers and angled bar racks, so-called fish guidance structures (FGS), to adapt and advance them in regard to safe fish passage and a successful economical implementation. This paper presents the results of an experimental investigation on louver and modified angled bar rack with and without a bottom overlay (BO) angled at 15กใ to the approach flow. For the former, the bars were angled 90กใ to the flow direction while for the latter they were angled 45กใ. The instantaneous flow velocities around the FGSs and in the bypass were measured in a laboratory open channel flume using ADV-probes (Acoustic Doppler velocimetry). The water depth was always 0.90 m with a mean flow velocity of 0.6 m/s. The longitudinal velocity near the bypass entrance in terms of approach velocity increased to 2.4, 1.6 and 1.4 for the louver, modified angled bar rack without BO and with BO, respectively. The highest traverse velocity towards the structure was found for the louver whereas low and no traverse velocities occurred for the modified angled bar rack without BO and with BO, respectively. Primary results of the live-fish experiments showed that fish guidance efficiency (FGE) e.g. for Barbel and Spirlin was the highest for the modified angled bar rack with BO, meaning that this structure creates a more favorable flow field than the others. To summarize, the findings of the present study provide an important foundation to continue development of the FGSs designed to guide central European target fish species to a downstream-bypass.
File Size : 933,819 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Hydro-environment
Date Published : 18/08/2015
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