Experimental study on dynamic forced pitch motions of rigid and flexible hydrofoils in towing tank

This paper presents a study on the hydrodynamics of rigid and flexible hydrofoils, in dynamic stall regime due to pitching actuation. An original experimental setup was developed to accommodate large scale innovative appendages, in the towing tank at Centrale Nantes, France. The original feature of the setup is its capability to simultaneously induce dynamical pitching motions to the appendages, and use optical fibers with arrays of fiber bragg gratings, for real-time strain monitoring. Forces and moments are measured dynamically with a six degreeof-freedom hydrodynamic balance. In this study, the Reynolds number considered ranged from Re = 160 000 to 1 000 000. The appendages are pitch-actuated with reduced frequencies k = πf c/V up to 0.14. Two appendages are considered. The first one is a rigid, thick, rectangular hydrofoil with a low aspect ratio (rudder-like hydrofoil). The second one is a flexible, thin, trapezoidal hydrofoil with a high aspect ratio (simplified propeller blade geometry). The data demonstrated setup capabilities to capture subtle flow phenomena such as as displacement of center of pressure, or delay of stall onset. Finally, the measurements present very good correlation between measured lift coefficients and strains of the flexible hydrofoil.

Subjects

Dynamic stall

Composite hydrofoil

Optical fiber

Towing tank

DDC Class

620: Engineering

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publishedVersion

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http://rightsstatements.org/vocab/InC/1.0/

Name

Simonet-ExperimentalStudyOnDynamicForcedPitchMotionsOfRigidAndFlexibleHy-1124-1-final.pdf

Type

Main Article

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7.43 MB

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Experimental study on dynamic forced pitch motions of rigid and flexible hydrofoils in towing tank