Hydraulic performance of fish guidance structures with curved bars – Part 2: flow fields

ABSTRACT

The current geometric designs of fish guidance structures with vertical bars for run-of-river hydropower plants result in high head losses and asymmetric turbine admission flow. To address these issues, we develop innovative curved bar designs and experimentally investigate different rack configurations with curved bars in a laboratory flume. The present paper (Part II) focuses on the hydraulic performance of the novel curved bar designs with regard to flow fields, while the companion paper (Part I) reports the results on the head losses. The detailed flow fields obtained by 3D velocity measurements show that the curved bars promote flow conditions favourable for both fish guidance and turbine operation. The flow straightening effect of the curved bars leads to quasi-symmetrical turbine admission flow and reduced head losses. The findings are discussed with regard to fish protection and guidance, and optimal engineering application.

Keywords:

• Curved-bar rack
• fish downstream migration
• fish guidance
• flow field
• hydraulic performance

Acknowledgements

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 727830, FITHydro (Fishfriendly Innovative Technologies for Hydropower). The authors would further like to thank the State Secretariat for Education, Research and Innovation (SERI) for their support. VAW’s activities in hydropower research are embedded in the Swiss Competence Centre for Energy Research, Supply of Electricity (SCCER-SoE), which is an initiative funded by the Swiss Confederation through Innosuisse (Swiss Innovation Agency).

ORCID

Claudia Beck http://orcid.org/0000-0001-9021-1378

Ismail Albayrak http://orcid.org/0000-0002-4613-6726

Julian Meister http://orcid.org/0000-0002-2715-6780

Robert M. Boes http://orcid.org/0000-0002-0319-976X

Additional information

Funding

This work was supported by Horizon 2020 Framework Programme [grant number 727830].