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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  and
B. S. Liebst
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
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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
Information
The Aeronautical Journal , Volume 107 , Issue 1067 , January 2003 , pp. 49 - 56
Copyright
Copyright © Royal Aeronautical Society 2003 

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