To maximize the effectiveness of fighter aircraft that operate well beyond the buffet onset boundary, the design of a new generation of fighter aircraft should account for both high maneuver capabilities and the aeroelastic buffet characteristics at high and wide range of angles of attack. The maneuver capabilities are achieved, for example in the F/A-18 fighter, through the combination of a leading-edge extension (LEX) with a delta wing, and the use of vertical tails. The effect of coupled and uncoupled bending and torsion modes on flexible twin-tail buffet is considered. This multidisciplinary problem is investigated using three sets of equations on a multi-block grid structure. The first set is the unsteady, compressible, laminar full Navier-Stokes equations which are used for obtaining the flow-field vector and the aerodynamic loads on the twin tails. The second set is the coupled aeroelastic equations which are used for obtaining the bending and torsional deflections of the twin tails. The third set is the grid-displacement equations which are used for updating the grid coordinates due to the tail deflections. The configuration is pitched at 30 deg angle of attack and the free-stream Mach number and Reynolds number are 0.3 and 1.25 million, respectively. Keeping the twin tails as rigid surfaces, the problem is solved for the initial flow conditions. Next, the problem is solved for the flexible twin-tails responses due to the unsteady loads produced by the vortex breakdown flow of the delta-wing leading-edge vortex cores. The configuration is investigated for the effect of coupled and uncoupled bending and torsion modes, using two different separation distances of the twin tail; the inboard and outboard positions. The computational results are in good agreement with the experimental data.
Coupled and uncoupled bending-torsion responses of twin-tail buffet
Journal of Fluids and Structures ; 12 , 6 ; 677-701
1998
25 Seiten, 27 Bilder, 1 Tabelle, 12 Quellen
Article (Journal)
English
Coupled and Uncoupled Bending-Torsion Responses of Twin-Tail Buffet
British Library Online Contents | 1997
|Adaptive Suction and Blowing for Twin-Tail Buffet Control
British Library Conference Proceedings | 1999
|