FIV2018 Paper Management System, FIV2018 Conference

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FLUID-STRUCTURE-INTERACTION OF A FLEXIBLE COMPOSITE HYDROFOIL IN FORCED ROTATIONAL OSCILLATION MOTION
Stefan Hoerner, Cyrille Bonamy, Thierry Maître, Dominique Thévenin

Last modified: 2018-05-07

Abstract


The presentation concerns experimental research of the behavior of a NACA0018 Hydrofoil. It consists of a composite structure from a rigid aluminum-milled leading edge and, beyond the first quarter of the cord, from a carbon-blade skeleton filled with silicone. The resulting structure is highly flexible, leading to large deformations when set into motion within the hydrodynamic tunnel at LEGI Grenoble.
Aim of the study is to investigate the impact of flexible structures as rotor blades of vertical-axis water turbines. It was observed that deformable blades can reduce peak loads and drag for working points with high angles of incidence, experiencing stall conditions. This is particularly important to improve efficiency at low tip-speed-ratio.
The foil deformation has been tracked using image analysis. A high-speed camera captures a grid projected onto the surface of the structure. The distance to the profile can then be recovered with high precision and a temporal resolution of about 4000 samples per second with the use of a spectral analysis of the grid deformation.
The presentation will show results from the surface tracking algorithm compared to force measurements.
See www.ovgu.de/hoerner/flexProfile.mp4 for a video of the hydrofoil.

Keywords


Large deformations; Adaptive structures; Hydropower;

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