Author(s): Inga Kleinewietfeld; Elena-Maria Klopries

Linked Author(s): Elena-Maria Klopries

Keywords: Tesla valve; Open-channel hydraulics; Turbulent flow; Fish guidance; Ecohydraulics; Diversion hydropower; Physical model

Abstract: Diversion hydropower plants often create competing flow fields at the confluence of the tailrace channel and the bypass reach, causing upstream-migrating fish to follow the stronger tailrace current and miss the fishway entrance. To counteract this “dead-end effect,” a physical–hydraulic barrier based on the directional flow properties of the Tesla valve is investigated. The concept aims to modify local hydraulics by generating turbulence to reduce the hydraulic attraction of the tailrace channel. In this study, the original Tesla valve geometry was transferred to an open -channel environment, an application largely unexplored in existing research. Initial flume experiments show a distinct hydraulic response: Upstream backwater, accelerated flow and water level reduction over the structures, pronounced turbulence and recirculation downstream. These first results provide the hydraulic basis for designing the upcoming ecohydraulic experiments.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.224

Year: 2026