Vibrating Profile in the Aerodynamic Tunnel – Identification of the Start of Flutter

Jan Kozanek; Vaclav Vlcek; Igor Zolotarev

Journal of Applied Nonlinear Dynamics

Miguel A. F. Sanjuan (editor), Albert C.J. Luo (editor)

Vibrating Profile in the Aerodynamic Tunnel – Identification of the Start of Flutter

Journal of Applied Nonlinear Dynamics 3(4) (2014) 317--323 | DOI:10.5890/JAND.2014.12.003

Jan Kozanek; Vaclav Vlcek; Igor Zolotarev

Department of Dynamics and Vibration, Institute of Thermomechanics ASCR,v.v.i., Dolejskova 5, 18200 Prague 8, Czech Republic

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Abstract

The experimental results for the vibrating NACA0015 profile elastically supported in a translation and rotation for a set of increasing Mach numbers of the airflow are presented. The profile was placed in the aerodynamic tunnel of the Institute of Thermomechanics ASCR. The support properties of the profile were modified by three additional masses to control the eigenfrequencies corresponding to transversal vibrations and verified by the identification of the complex eigenvalues (eigenfrequencies, damping) for zero flow velocity in laboratory. The transversal free vibrations as the time functions are graphically depicted for stable vibrations and in the cases of the starting flutter. The start of the flutter was determined from free vibrations of kinematically excited profile. The complex eigenvalues were identified as the functions of Mach number including corresponding limits of the system aeroelastic stability.

Acknowledgments

The authors acknowledge the Grant Agency of the Czech Republic for supporting this work under Grant No. P101/13-10527S ”Subsonic flutter analysis of elastically supported airfoils using interferometry and CFD”. The paper has been presented during 12th Conference on Dynamical Systems—Theory and Applications, December 2–5, 2013, Lodz, Poland.

References

[1]	Kozanek, J., Vlcek, V., and Zolotarev, I. (2013), Vibrating profile kinematics in the start of flutter, Proc. of the 12th Conference on Dynamical Systems - Applications, ed. J. Awrejcewicz and others, Lodz, Poland, 667–676.

[2] Vlcek, V. and Kozanek, J. (2011), Preliminary interferometry measurements of flow field around fluttering NACA0015 profile, Acta Technica, 56, 379–387.
[3] Awrejcewicz, J. (2012), Classical Mechanics: Dynamics, Springer, New York.
[4] He, J. and Fu, Z.-F. (2004) Modal Analysis, Butterworth Heinemann, Oxford.