Numerical Simulation and Experimental Verification of Downstream Fish migration in a Kaplan turbine

Fish migrating downstream may face an increased risk of injury when passing through hydropower turbines. The overall influence on fish populations remains unknown. Still, it is undoubtedly linked to the damage potential of the turbines, the stage of maturity and the size of the migrating individuals as well as the proportion of migrating fish in relation to the total population. The sources of injury are usually the contact to the turbine blade and the rapid pressure drop in the turbine as well as shear forces, and large-scale turbulence. The authors investigated the conditions experienced by fish migrating through a 5-bladed vertical Kaplan turbine, each of the two units with a nominal power of 45 MW. Therefore, so-called "Barotrauma Detection Sensors (BDS)"were applied to determine the physical parameters during the turbine passages. Additionally, live fish, fitted externally with Barotrauma Detection Sensors, were introduced.