Hostname: page-component-77c89778f8-7drxs Total loading time: 0 Render date: 2024-07-16T10:20:53.706Z Has data issue: false hasContentIssue false
  • English
  • Français

Method for aerodynamic unsteady forces time calculations on an F/A-18 aircraft

Published online by Cambridge University Press:  03 February 2016

D. E. Biskri  and
R. M. Botez
D. E. Biskri
Affiliation:
École de technologie supérieure, Department of Automated Production Engineering, Montréal, Québec, Canada
R. M. Botez
Affiliation:
École de technologie supérieure, Department of Automated Production Engineering, Montréal, Québec, Canada
Get access Rights & Permissions [Opens in a new window]

Abstract

In this paper, a new original method based on the least squares method is presented for the conversion of unsteady aerodynamic forces from frequency into Laplace domain, in which the error is written in an analytical form as a function of the Laplace variable, similar to the analytical form of the aerodynamic forces calculated by use of the least squares method. This method is applied on an F/A-18 aircraft (14 symmetric and 14 anti-symmetric modes) for one Mach number and for a set of 14 reduced frequencies. Two different types of results are obtained and analysed: aerodynamic force approximations in the Laplace domain and flutter speeds and frequencies values. For a better comparison of these results, different lag term numbers are used. Results obtained by this new method are better in terms of execution speed and precision than the results obtained by use of the least squares method.

Type
Research Article
Information
The Aeronautical Journal , Volume 112 , Issue 1127 , January 2008 , pp. 27 - 32
Copyright
Copyright © Royal Aeronautical Society 2008 

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

1. Tiffany, S.H. and Adams, WM., Nonlinear programming extensions to rational function approximation of unsteady aerodynamics, July 1988, NASA TP-2776.Google Scholar
2. Edwards, J.W., Unsteady aerodynamic modeling and active aeroelastic control, February 1977, SUDAAR 504, Stanford University, Stanford, CA.Google Scholar
3. Roger, K.L., Airplane math modeling methods for active control design, August 1977, Structural aspects of active controls AGARD CP-228, pp 4.1–4.11.Google Scholar
4. Vepa, R., Finite state modeling of aeroelastic system, February 1977, NASA CR-2779.Google Scholar
5. Karpel, M., Design for flutter suppression and gust alleviation using state space modeling, J Aircr, 1982, 19, (3), pp 221–227.Google Scholar
6. Tiffany, S.H. and Adams, W.M., Fitting aerodynamic forces in the Laplace domain: an application of a nonlinear nongradient technique to multilevel constrained optimization, 1984, NASA TM 86317.Google Scholar
7. Dunn, H.J., An analytical technique for approximating unsteady aerodynamics in the time domain, 1980, NASA TP-1738.Google Scholar
8. Poirion, F., Multi-mach rational approximation to generalized aerodynamic forces, J Aircr, 1996, 33, (6), pp 1199–1201.Google Scholar
9. Cotoi, I. and Botez, R.M., Method of unsteady aerodynamic forces approximation for aeroservoelastic interactions, AIAA J Guidance, Control and Dynamics, 2002, 25, (5), pp 985–987.Google Scholar
10. Cotoi, I., Dinu, A.D. and Botez, R.M., Model order reduction for aeroservoelasticity studies by use of LRSRM and LRSM algorithms, 2004, 24th International Congress of Aeronautical Sciences ICAS 2004, Yokohama, Japan, 30 August-3 September, 2004.Google Scholar
11. Hiliuta, A., Botez, R.M. and Brenner, M., Approximation of unsteady aerodynamic forces by use of fuzzy techniques, 2005, 46th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, Austin, TX, 18-21 April, 2005.Google Scholar
12. Gupta, K.K., Development and application of an integrated multidisci-plinary analysis capability, Int J for Numerical Methods in Engineering, 1997, 40, (3), pp 533–550.Google Scholar