Hostname: page-component-78c5997874-ndw9j Total loading time: 0 Render date: 2024-11-10T12:50:57.872Z Has data issue: false hasContentIssue false

Identification of freeplay and aerodynamic nonlinearities in a 2D aerofoil system with via higher-order spectra

Part of: APISAT 2015

Published online by Cambridge University Press:  04 October 2017

M. Candon*
Affiliation:
RMIT University, School of Engineering (Aerospace and Aviation), Melbourne, Australia
R. Carrese
Affiliation:
RMIT University, School of Engineering (Aerospace and Aviation), Melbourne, Australia
H. Ogawa
Affiliation:
RMIT University, School of Engineering (Aerospace and Aviation), Melbourne, Australia
P. Marzocca
Affiliation:
RMIT University, School of Engineering (Aerospace and Aviation), Melbourne, Australia

Abstract

Higher-Order Spectra (HOS) are used to characterise the nonlinear aeroelastic behaviour of a plunging and pitching 2-degree-of-freedom aerofoil system by diagnosing structural and/or aerodynamic nonlinearities via the nonlinear spectral content of the computed displacement signals. The nonlinear aeroelastic predictions are obtained from high-fidelity viscous fluid-structure interaction simulations. The power spectral, bi-spectral and tri-spectral densities are used to provide insight into the functional form of both freeplay and inviscid/viscous aerodynamic nonlinearities with the system displaying both low- and high-amplitude Limit Cycle Oscillation (LCO). It is shown that in the absence of aerodynamic nonlinearity (low-amplitude LCO) the system is characterised by cubic phase coupling only. Furthermore, when the amplitude of the oscillations becomes large, aerodynamic nonlinearities become prevalent and are characterised by quadratic phase coupling. Physical insights into the nonlinearities are provided in the form of phase-plane diagrams, pressure coefficient distributions and Mach number flowfield contours.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society 2017 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Dowell, E.H. A Modern Course in Aeroelasticity, 2015, Springer International Publishing, Cham, Switzerland.Google Scholar
2. Ni, K., Hu, P., Zhao, H. and Dowell, E.H. Flutter and lco of an all–movable horizontal tail with freeplay, 53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, January, 2012, Honolulu, Hawaii, US.Google Scholar
3. Price, S.J., Lee, B.H.K. and Alighanbari, H. Postinstability behavior of a two–dimensional airfoil with a structural nonlinearity, J Aircraft, November 1994, 31, (6), pp 1395-1400.Google Scholar
4. Conner, M.D., Tang, D.M., Dowell, E.H. and Virgin, N. Nonlinear behavior of a typical airfoil section with control surface freeplay: A numerical and experimental study, J Fluids and Structures, January 1997, 11, (1), pp 89-109.Google Scholar
5. Tang, D.M., Dowell, E.H. and Virgin, N. Limit cycle behaviour of an airfoil with a control surface, J Fluids and Structures, October 1998, 12, (7), pp 839-858.Google Scholar
6. Kim, D.H. and Lee, I. Transonic and low-supersonic aeroelastic analysis of a two-degree-of freedom airfoil with a freeplay nonlinearity, J Sound Sound and Vibration, July 2000, 234, (5), pp 859-880.Google Scholar
7. Dowell, E.H., Thomas, J.P. and Hall, K.C. Transonic limit cycle oscillation analysis using reduced order aerodynamic models, J Fluids and Structures, January 2003, 19, (1), pp 17-27.Google Scholar
8. Tijdeman, H. Investigations of the Transonic Flow Around Oscillating Airfoils, PhD Dissertation, TU Delft, The Netherlands, 1977.Google Scholar
9. Thomas, J.P., Dowell, E.H. and Hall, K.C. Nonlinear inviscid aerodynamic effects on transonic divergence, flutter, and limit-cycle oscillations, J Aircraft, April 2003, 40, (2), pp 303-313.Google Scholar
10. Kholodar, D.B., Thomas, J.P., Dowell, E.H. and Hall, K.C. Parametric study of flutter for an airfoil in inviscid transonic flow, AIAA J, March 2003, 40, (2), pp 638-646.Google Scholar
11. Weber, S., Jones, K.D., Ekaterinaris, J.A. and Platzer, M.F. Transonic flutter computations for the NLR 7301 supercritical airfoil, Aerospace Science and Technology, June 2001, 5, (4), pp 293-304.CrossRefGoogle Scholar
12. Schewe, H., Mai, G. and Dietz, G. Nonlinear effects in transonic flutter with emphasis on manifestations of limit cycle oscillations, J Fluids and Structures, August 2003, 18, (1), pp 3-22.Google Scholar
13. Dietz, G. and Mai, H. Experiments on heave/pitch limit-cycle oscillations of a supercritical airfoil close to the transonic dip, J Fluids and Structures, January 2004, 19, (1), pp 1-16.Google Scholar
14. Thomas, J.P., Dowell, E.H. and Hall, K.C. Modeling viscous transonic limit-cycle oscillation behavior using a harmonic balance approach, J Aircraft, November 2004, 41, (6), pp 1266-1274.Google Scholar
15. Nikias, N.C. and Petropulu, A.P. Higher-Order Spectra Analysis A Nonlinear Signal Processing Framework, 1993, Prentice-Hall, New Jersey, US.Google Scholar
16. Bendant, J.S. and Piersol, A.G. Random Data Analysis and Measurement Procedures, 2000, Wiley, New York, US.Google Scholar
17. Worden, K. and Tomlinson, G.R. Nonlinearity in Structural Dynamics: Detection, Identification and Modelling, 2001, IoP Publishing, Bristol, UK.Google Scholar
18. Kerschen, G., Worden, K., Vakakis, A.F. and Golinval, J.C. Past, present and future of nonlinear system identification in structural dynamics, Mech Systems and Signal Processing, April 2006, 20, (3), pp 505-592.CrossRefGoogle Scholar
19. Silva, W.A. Identification of nonlinear aeroelastic systems based on the volterra theory: Progress and opportunities, Mech Systems and Signal Processing, January 2005, 39, (1–2), pp 25-62.Google Scholar
20. Silva, W.A., Stragnac, T. and Muhammad, R.J. Higher–order spectral analysis of a nonlinear pitch and plunge apparatus, Proceedings of the 46th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, April 2005, Austin, Texas, US.Google Scholar
21. Hajj, M.R. and Silva, W.A. Nonlinear flutter aspects of the flexible high-speed civil transport semispan model, J Aircraft, September 2004, 41, (5), pp 1202-1208.CrossRefGoogle Scholar
22. Silva, W.A., Dunn, S. and Muhammad, R.J. Higher-order spectral analysis of f-18 flight flutter data, Proceedings of the 46th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, April 2005, Austin, Texas, US.CrossRefGoogle Scholar
23. Hajj, M.R. and Beran, P.S. Higher-order spectral analysis of limit cycle oscillations of fighter aircraft, J Aircraft, November 2008, 45, (6), pp 1917-1923.Google Scholar
24. Marzocca, P., Librescu, L. and Silva, W.A. Nonlinear open-/closed loop aeroelastic analysis of airfoils via volterra series, AIAA J, April 2004, 42, (4), pp 673-686.Google Scholar
25. On the transonic-dip mechanism of flutter of a sweptback wing, AIAA J, July 1979, 17, (7), pp 793-795.Google Scholar
26. Isogai, K. On the transonic-dip mechanism of flutter of a sweptback wing. II, AIAA J, September 1981, 19, (9), pp 1240-1242.Google Scholar
27. Workbench Users Guide Release 16.2, Ansys Academic Research, 2015, Pennsylvania, US.Google Scholar
28. Spalart, P.R. and Allmaras, S.R. A one equation turbulence model for aerodynamic flows, La Recherche Aerospatiale, 1994, 1, pp 5-21.Google Scholar
29. Hall, K.C., Thomas, J.P. and Dowell, H.H. Proper orthogonal decomposition technique for transonic unsteady aerodynamic flows, AIAA J, October 2000, 38, (10), pp 1853-1862.Google Scholar
30. Timme, S. and Badcock, S. J. Transonic aeroelastic instability searches using sampling and aerodynamic model hierarchy, AIAA J, June 2011, 49, (6), pp 1191-1201.Google Scholar
31. Subba, T. and Gabr, M. An Introduction to Bispectral Analysis and Bilinear Time Series, Lecture Notes in Statistics, 1984, Springer-Verlag, New York, US.Google Scholar
32. Dalle Molle, J.W. and Hinich, M.J. The trispectrum, Proceedings of the Workshop Higher Order Spectral Analysis, June 1989, Vale, Colorado, US.Google Scholar
33. Oppenheim, R.W. and Schafer, A.V. Discrete-Time Signal Processing, 1999, Prentice Hall, New Jersey, US.Google Scholar
34. Hickey, D., Worden, K., Platten, M.F., Wright, J.R. and Cooper, J.W. Higher-order spectra for identification of nonlinear modal coupling, Mech Systems and Signal Processing, October 2009, 23, (4), pp 1037-1061.Google Scholar