An experimental study on fish-friendly trashracks – Part 2. Angled trashracks

Abstract

Experimental results for fish-friendly trashracks placed in an open water channel are presented. Model trashracks with different bar shapes, spacing and angles were tested. The numerous configurations provided results on head losses and on changes in velocity along the rack for a large range of situations, including fish-friendly trashracks. Previous head-loss equations found in the literature were applied to these configurations and were compared with measurements. A new head-loss equation is proposed that takes into account the effect of the different tested parameters. Velocity measurements provided new results and answers concerning downstream-migration aspects such as admissible approach velocities and guidance efficiency as a function of the trashrack angle.

Keywords:

• Angled trashrack
• downstream migration
• experimental hydraulics
• head loss
• velocity distribution

Acknowledgements

This work was funded by the European Regional Development Fund (ERDF), the Région Poitou-Charentes, ONEMA, ADEME, CNR, SHEM and France Hydro-Electricité. Their support is greatly appreciated.