The Flow Field Acting on the Fluttering Profile, Kinematics, Forces and Total Moment

Kozánek, Jan; Vlček, Václav; Zolotarev, Igor

doi:10.1142/s0219455413400099

Cited by 5 publications

(3 citation statements)

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“…Kinematics of the fluttering profile was quite different compared to our previous experiments with higher rotational frequencies (see [5]). The relation between shift and pitch angle had two loops, see…”

Section: C) Profile Kinematicscontrasting

confidence: 86%

Innovation of the Experimental Facility for the Study of Flutter in the Institute of Thermomechanics AS CR and Some Results Obtained from Initial Experiments

Vlček¹,

Štěpán

Zolotarev³

et al. 2016

AMM

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Experimental facility situated in the test section of the wind tunnel suction type was adjusted both in the total construction and in the construction of the fluttering body, the methodology of the measurement and evaluation of the flow and dynamic parameters during flutter were also changed. Preserved was the conception of the NACA0015 profile with two degrees of freedom, rotational and translational. Torque elasticity was now realized by the coil spring and changed by different length of this spring or by different diameter of the spring wire. The pitch angle of the profile was now measured by the magnetic rotary encoder. The translational position was indicated by the magnetic linear encoder and was centered by plane springs situated on both ends of the shiftable frame. With this model the testing measurement was realized by its self-excited vibration of flutter type in the range of Mach numbers M=0.20-0.215 and Reynolds numbers 263 000 – 283 000. Results obtained with M=0.21 and Re=276 000 are presented.

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Section: C) Profile Kinematicscontrasting

confidence: 86%

Innovation of the Experimental Facility for the Study of Flutter in the Institute of Thermomechanics AS CR and Some Results Obtained from Initial Experiments

Vlček¹,

Štěpán

Zolotarev³

et al. 2016

AMM

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“…The model design builds on previous experience obtained in the Institute of Thermomechanics in the years 2006-2012, when self-oscillating models of the NACA0015 and DCA18% airfoils with two degrees of freedom were designed and the methodology of the measurements developed [6,7,3]. The airfoil, supported by a linear and torsional springs, is fixed in a suctiontype wind tunnel with optical access through the side walls for Schlieren visualizations and interferometric measurements of the flow field.…”

Section: Methodsmentioning

confidence: 99%

Turbulence intensity measurement in the wind tunnel used for airfoil flutter investigation

et al. 2017

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Abstract. The paper reports on hot wire turbulence intensity measurements performed in the entry of a suction-type wind tunnel, used for investigation of flow-induced vibration of airfoils and slender structures. The airfoil is elastically supported with two degrees of freedom (pitch and plunge) in the test section of the wind tunnel with lateral optical access for interferometric measurements, and free to oscillate. The turbulence intensity was measured for velocities up to M = 0.3 i) with the airfoil blocked, ii) with the airfoil self-oscillating. Measurements were performed for a free inlet and further with two different turbulence grids generating increased turbulence intensity levels. For the free inlet and static airfoil, the turbulence intensity lies below 0.4%. The turbulence grids G1 and G2 increase the turbulence level up to 1.8% and 2.6%, respectively. When the airfoil is free to oscillate due to fluid-structure interaction, its motion disturbs the surrounding flow field and increases the measured turbulence intensity levels up to 5%.

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“…The physical model is an original design of an airfoil with two degrees of freedom -pitch and plunge, installed in a test section of a suction-type wind tunnel in Nový Knín [3,4,5]. The NACA0015 airfoil is supported by vertical quides, freely moving in the vertical direction and rotating around the elastic axis in 1/3 of the chord length (see Fig.…”

Section: Methodsmentioning

confidence: 99%

Evaluation of Interferograms of Unsteady Subsonic Airflow Past a Fluttering Airfoil

Šidlof¹,

Riss²,

Vlček³

2016

Topical Problems of Fluid Mechanics 2016

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The paper reports on time-resolved interferometric measurements of unsteady flow fields around a fluttering NACA0015 airfoil. A mechanical model with two degrees of freedom (pitch and plunge) has been designed and tested in a high-speed subsonic wind tunnel. Aeroelastic instability of the classical flutter and dynamic stall type has been observed in the Mach number range M = 0.2 -0.5. The interferograms were recorded using a Mach-Zehnder interferometer and a high-speed camera. An in-house software IFGPro was developed for the postprocessing and evaluation of the interferogram sequences, yielding pressure distribution, lift and drag force on the airfoil.

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The Flow Field Acting on the Fluttering Profile, Kinematics, Forces and Total Moment

Cited by 5 publications

References 0 publications

Innovation of the Experimental Facility for the Study of Flutter in the Institute of Thermomechanics AS CR and Some Results Obtained from Initial Experiments

Innovation of the Experimental Facility for the Study of Flutter in the Institute of Thermomechanics AS CR and Some Results Obtained from Initial Experiments

Turbulence intensity measurement in the wind tunnel used for airfoil flutter investigation

Evaluation of Interferograms of Unsteady Subsonic Airflow Past a Fluttering Airfoil

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