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Computational simulation of wing rock in three degrees-of-freedom for a generic fighter with chine-shaped forebody

Published online by Cambridge University Press:  04 July 2016

A. A. Saad
Affiliation:
Department of Aeronautics and AstronauticsAir Force Institute of TechnologyWright-Patterson Air Force BaseOhio, USA
B. S. Liebst
Affiliation:
Department of Aeronautics and AstronauticsAir Force Institute of TechnologyWright-Patterson Air Force BaseOhio, USA

Abstract

Modern fighter aircraft have been associated with lateral self-excited limit cycle oscillation known as ‘wing rock’. Simulations of wing rock have been encouraged to develop a complete understanding of the fluid mechanism that triggers and drives the oscillation, as well as for prediction purposes. Previous simulations of wing rock in wind/water tunnels were almost exclusively limited to a single degree-of-freedom in roll, due to the difficulty encountered in mounting the model to freely oscillate in more than one degree-of-freedom. Numerical simulations, utilising computational fluid dynamics, were also limited to roll-only degree-of-freedom. The loss of simulation accuracy due to the reduction of the actual wing rock degrees-of-freedom to roll-only has not as yet been fully investigated. In this study wing rock is numerically simulated in three degrees-of-freedom: roll, sideslip, and vertical motion for a generic fighter model. The unsteady Euler equations are coupled with the rigid-body dynamic equations through an innovative sub-iteration algorithm to simultaneously solve the coupled equations. The effect of including the sideslip and vertical degrees-of-freedom was found to delay the onset angle-of-attack of wing rock by 5° and reduce the limit cycle amplitude by about 50% with the frequency remained almost unchanged.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society 2003 

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References

1. Nguyen, L.T., Yip, L.P. and Chambers, J.R. Self-induced wing rock of slender delta wings, August 1981, AIAA Paper 81–1883.Google Scholar
2. Levin, D. and Katz, J. Dynamic load measurements with delta wings undergoing self-induced roll-oscillations, J Aircr, January 1984, 21, (l),pp 3036.Google Scholar
3. Brandon, J.M. and Nguyen, L.T. Experimental study of effects of forebody geometry on high angle-of-attack static and dynamicstability, January 1986, AIAA Paper 86–0331.Google Scholar
4. Fratello, D.J., Croom, M.A., Nguyen, L.T., and Domack, C.S. Use of the updated NASA Langley radio-controlled drop model technique for high-alpha studies of the X-29A configuration, August 1987, AIAA Paper 87–2559.Google Scholar
5. Konstadinopoulus, P., Mook, D.T. and Nayfeh, A.H. Subsonic wing rock of slender delta wings, J Aircr, March 1985, 22, (3), pp 223228.Google Scholar
6. Ericson, L.E. The fluid mechanics of slender wing rock, J Aircr, May 1984, 21, (5), pp 322328.Google Scholar
7. Lee, E.M. and Batina, J.T. Conical Euler simulations of wing rock for a delta wing planform, J Aircr, January 1991, 28, (1), pp 9496.Google Scholar
8. Kandil, O.A. and Salman, A.A. Three-dimensional simulation of slender delta wing rock and divergence, 1992, AIAA Paper 92–0280.Google Scholar
9. Gordnier, R.E. and Visbal, M.R. Numerical simulation of delta-wing roll, January 1993, AIAA Paper 93–0554.Google Scholar
10. Chaderjian, N.M. Navier-Stokes prediction of large-amplitude delta-wing roll oscillations, J Aircr, November-December 1994, 31, (6), pp 13331340.Google Scholar
11. Chaderjian, N.M. and Schiff, L.B. Numerical simulation of forced and free-to-roll delta-wing motions, J Aircr, January-February 1996, 33, (l), pp 93100.Google Scholar
12. Saad, A.A. and Liebst, B.S. An analytical criterion for the prediction and analysis of wing rock onset, August 1999, AIAA Paper 99–4099.Google Scholar
13.AGARD Computation aerodynamics based on Euler equations, 1991, Technical Report, AGARD-AG-325.Google Scholar
14. Ravi, R., and Mason, W.H. A computational study on directional stability of chine-shaped forebodies at high-α, January 1992, AIAA Paper 92–0030.Google Scholar
15. Wurtzler, K. Numerical analysis of a chined forebody with asymmetric strakes, January 1993, AIAA Paper 93–0051,.Google Scholar
16. Hoffmann, K. and Chiang, S. Computational fluid dynamics for engineers - Volume II, 1993, Wichita, KS, USA.Google Scholar
17. Jackson, P.J. (Ed) Jane’s All the World’s Aircraft (1999–2000), 1999, Franklin Watts, New York.Google Scholar
18. Whitfield, D.L. Three-Dimensional Unsteady Euler Equation Solutions Using Flux Vector Splitting, June 1984, printed notes for a short course on numerical grid generation, Mississippi State University.Google Scholar
19. Saad, A.A. Simulation and Analysis of Wing Rock Physics for a Generic Fighter Model with Three Degrees-of-Freedom, October 2000, PhD dissertation, AFIT/DS/ENY/00-01, School of Engineering, Air Force Institute of Technology (AU), WPAFB OH, USA.Google Scholar
20. Beam, R.M. and Warming, R.F. An implicit factored scheme for the compressible Navier-Stokes equations, AIAA J, April 1978, 16, (4), pp 393402.Google Scholar
21. Pulliam, T.H. and Chaussee, D.S. A diagonal form of an implicit approximate-factorization algorithm, J Computational Physics, 1981, 39, (2), pp 347363.Google Scholar
22. Polhamus, E.C. Predictions of vortex-lift characteristics by a leading-edge suction analogy, J Aircr, 1971, 8, (4), pp 193199.Google Scholar