The control of vortical flow on a delta wing at high angles of attack

Author(s):  
N. WOOD ◽  
L. ROBERTS
2003 ◽  
Vol 9 (5) ◽  
pp. 583-604 ◽  
Author(s):  
Essam F. Sheta

A multidisciplinary analysis of vertical tail buffeting and buffeting alleviation of generic fighter aircraft is conducted. This complex multidisciplinary problem is solved for the fluid dynamics, structure dynamics, fluid-structure coupling, and grid deformation using a computing environment that controls the temporal synchronization of the data transfer between the analysis modules. The generic fighter aircraft consists of a sharp-edged delta wing with an aspect ratio of one and a swept-back, flexible, vertical twin tail with a taper ratio of 0.23. Twin streamwise fences are located at the 30% chord-station of the delta wing. The fences are used to alter the vortical flow and to delay the onset of vortex breakdown above the delta wing, in order to alleviate the twin-tail buffeting. The effect of the geometrical shape of the fences on the buffeting responses is investigated. The performance of the fences over a wide range of high angles of attack is also investigated. The trapezoidal configuration of the fences at a taper ratio of 0.7 produced the most favorable results. The results indicated that the fences are effective in reducing the aeroelastic loads and responses, especially at angles of attack less than 30°.


AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 1612-1620
Author(s):  
A. Honkan ◽  
J. Andreopoulos

2013 ◽  
Vol 444-445 ◽  
pp. 286-292
Author(s):  
Bing Han ◽  
Min Xu ◽  
Xi Pei ◽  
Xiao Min An

The effect of slender body on the rolling characteristics of a double delta wing is found by comparing the numerical simulation results of the double delta wing and wing-body configuration. The coupled computation system solving the Navier-Stokes equations and the rolling motion equation alternatively to obtain the unsteady vortical flow around the two configurations while rolling. The results conclusively showed the upwash effect of the slender body enhanced the energy of strake vortex and merged vortex.The aerodynamic lag of double delta wing is weak, contrarily, the time lag effect of the wing-body configuration is significant. The asymmetry vortices structure nearby the trailing edge are believed to be the main reason for the unsteady time lag effect.


1994 ◽  
Vol 98 (975) ◽  
pp. 159-170 ◽  
Author(s):  
P. R. Viswanath ◽  
S. R. Patil

AbstractAn experimental study investigating the aerodynamic characteristics of generic delta wing-body combinations up to high angles of attack was carried out at a subsonic Mach number. Three delta wings having sharp leading edges and sweep angles of 50°, 60° and 70° were tested with two forebody configurations providing a variation of the nose fineness ratio. Measurements made included six-component forces and moments, limited static pressures on the wing lee-side and surface flow visualisation studies. The results showed symmetric flow features up to an incidence of about 25°, beyond which significant asymmetry was evident due to wing vortex breakdown, forebody vortex asymmetry or both. At higher incidence, varying degrees of forebody-wing vortex interaction effects were seen in the mean loads, which depended on the wing sweep and the nose fineness ratio. The vortex breakdown on these wings was found to be a gradual process, as implied by the wing pressures and the mean aerodynamic loads. Effects of forebody vortex asymmetry on the wing-body aerodynamics have also been assessed. Comparison of Datcom estimates with experimental data of longitudinal aerodynamic characteristics on all three wing-body combinations indicated good agreement in the symmetric flow regime.


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