Cross-Flow Tidal Turbines with Highly Flexible Blades—Experimental Flow Field Investigations at Strong Fluid–Structure Interactions

Oscillating hydrofoils were installed in a water tunnel as surrogate model for hydrokinetic cross-flow tidal turbine, enabling the study of effect flexible blades on performance those devices with high ecological potential. The focuses single tip-speed ratio (equal to 2), key non-dimensional parameter describing operating point, and solidity 1.5), quantifying robustness turbine shape. Both parameters are standard values turbines. Those lead highly dynamic characteristics flow field dominated by stall. is investigated at blade level using high-speed particle image velocimetry measurements. Strong fluid–structure interactions significant structural deformations modified fields. flexibility shown significantly reduce duration periodic stall regime; this observation achieved through systematic comparison field, quantitative evaluation degree chaotic changes wake. In manner, provides insights into mechanisms passive control