Aerospace Science and Technology
Mohammad Reza Hashemi; Seyyed Majid Malek Jafarian; Mojtaba Dehghan Manshadi
Abstract
In this research, the effects of canard flow on a diamond wing equipped with LEX, same as new-generation fighters, have been investigated, using a closed-circuit wind tunnel. All tests were performed at a speed of 12.5 meters per second, which is equivalent to Reynolds number 214000 based on model length. ...
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In this research, the effects of canard flow on a diamond wing equipped with LEX, same as new-generation fighters, have been investigated, using a closed-circuit wind tunnel. All tests were performed at a speed of 12.5 meters per second, which is equivalent to Reynolds number 214000 based on model length. The pressure measurement is conducted by the five-hole probe, which is normalized by the dynamic pressure of the free stream velocity in four cross-sections over the wing. The results showed that at a low angle of attack, a strong vortex is produced at the leading-edge of the wing, called the leading-edge vortex. As the leading-edge vortex moves downstream, the diameter of its core and distance from the wing surface increases. At higher angles of attack, LEX, canard and body vortices are also present, which combine with the leading-edge vortex and cover a large cross-flow area over the wing. At these angles of attack, the movement of the vortical flow downstream leads to an increase in the pressure coefficient of the vortex core, which indicates the beginning of instability and vortex breakdown. The results showed that the pressure increase in the vortex core was not sudden and this results in that the breakdown phenomenon in the diamond wing equipped with LEX and canard occurs slowly.
M. Manshadi; A. Sharafi; M.H. Soltani
Volume 9, Issue 2 , September 2012, , Pages 15-24
Abstract
An extensive experimental investigation is conducted to study the effect of canard position relative to the fuselage reference line on the aerodynamic forces of a fighter type configuration model. Aerodynamic forces at different flight conditions are measured in a subsonic wind tunnel. The wing and the ...
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An extensive experimental investigation is conducted to study the effect of canard position relative to the fuselage reference line on the aerodynamic forces of a fighter type configuration model. Aerodynamic forces at different flight conditions are measured in a subsonic wind tunnel. The wing and the canard have triquetrous shapes. Experiments are conducted at Reynolds number of 342209 and at 0 to 40 degree angles of attack. The results show that canard increases the lift and drag forces while it decreases the static stability of the model. The canard at itandrsquo;s up position increases the aerodynamic forces and decreases the static stability i.e., superior maneuver capability. Furthermore, when the forward position of the canard is considered, both lift and drag are increased; however, the overall aerodynamic efficiency and also more static stability are improved. The canard at up and forward position respect to the wing-body is an appropriate selection for the best performance at moderate to high angles of attack among the various wing-canard-body configurations.
