Hydrodynamic Damping of a Fluttering Hydrofoil in High-speed Flows
Journal article, Peer reviewed
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http://hdl.handle.net/11250/2596883Utgivelsesdato
2018Metadata
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Originalversjon
International Journal of Fluid Machinery and Systems. 2018, 11 (2), 146-153. 10.5293/IJFMS.2018.11.2.146Sammendrag
A hydrofoil resembling a high head Francis runner blade was submerged in a rectangular channel and attached to the walls in a fixed-beam configuration. The hydrofoil was excited by piezoelectric Macrofiber composite actuators (MFCs), and the vibration was measured at the trailing edge with Laser Doppler Vibrometry (LDV) and semiconductor strain gauges. The hydrofoil was exposed to water velocities ranging from 0 to 25 m/s. Lock-in occurred at approx. 11m/s. The damping increased linearly with the water velocity, with a slope of 0.02 %/(m/s) below lock-in, and 0.13 %/(m/s) above lock-in. The natural frequency of the foil increased slightly