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

Downward migrating fish can be damaged when passing through turbines in the direction upstream to downstream. The overall influence on the fish population is not known yet. In recent decades, many publications with steady-state CFD calculations for the passage of fish have been published. However, transient CFD calculations show that the range in which fish pass the runner itself is not easily predictable but rather random, influenced by the current position of the runner, thus affecting the probability of survival. The pressures, which are also well represented by steady-state CFD calculations, are compared by applying “Live Fish” (typical types for the middle of Europe) as well as “Barotrauma Detections Sensors (BDS)” which were exposed to the area of the turbine intake at different heights and monitored during downstream migration.