Passive flow control mechanisms with bioinspired flexible blades in cross-flow tidal turbines

Stefan Hoerner (1, 2) , Shokoofeh Abbaszadeh (1) , Olivier Cleynen (1) , Cyrille Bonamy (2) , Thierry Maître (2) , Dominique Thévenin (1)

1 OVGU - Otto-von-Guericke-Universität Magdeburg = Otto-von-Guericke University [Magdeburg]
2 LEGI - Laboratoire des Écoulements Géophysiques et Industriels [Grenoble]

State-of-the-art technologies for wind and tidal energy exploitation focus mostly on axial turbines. However, cross-flow hydrokinetic tidal turbines possess interesting features, such as higher area-based power density in array installations and shallow water, as well as a generally simpler design. Up to now, the highly unsteady flow conditions and cyclic blade stall have hindered deployment at large scales because of the resulting low single-turbine efficiency and fatigue failure challenges. Concepts exist which overcome these drawbacks by actively controlling the flow, at the cost of increased mechatronical complexity. Here, we propose a bioinspired approach with hyperflexible turbine blades. The rotor naturally adapts to the flow through deformation, reducing flow separation and stall in a passive manner. This results in higher efficiency and increased turbine lifetime through decreased structural loads, without compromising on the simplicity of the design. Graphic abstract

Domains: Materials; Fluids mechanics [physics.class-ph]; Materials and structures in mechanics [physics.class-ph]

Stefan Hoerner, Shokoofeh Abbaszadeh, Olivier Cleynen, Cyrille Bonamy, Thierry Maître, et al.. Passive flow control mechanisms with bioinspired flexible blades in cross-flow tidal turbines. Experiments in Fluids, 2021, 62 (5), ⟨10.1007/s00348-021-03186-8⟩. ⟨hal-03221487⟩