Abstract
Fighter aircrafts with high maneuverability and swiftness are due to fuselage effects, caused by canard-fuselage-main wing configuration. Even though the flows around fighters are highly complex, mostly they create rolled-up vortices capable to delay stalls and increase maximum lifts (Calderon, Wang & Gursul, 2012; Mitchell & Delery, 2001; Boelens, 2012; Chen, Liu, Guo & Qu, 2015). The vortex dynamics analysis method employment is introduced, in this case we focus only on the fighter canard. It characterizes the vortex core, develops the pitching moment & main wing total lift, and exploits the vortex centre visualization, the strength, negative surface pressure and its trajectory.This paper explains the influence of the fighter fuselage, it generates rolled-up vortex effects, causes the flow deflected by the fighter fuselage head, strengthen the vortex centre to become vortex core. Above the aircraft head, due to the curved contour head effect, the second vortex centers are developed makes the vortex center above the head more dynamic. Comparing with fighter without fuselage, the flow property changes, for Chengdu J-10-like model with fuselage, are concentrated at the canard leading edge, where the negative pressures are stronger, since the maximum axial velocities of the vortex centre are higher, and give more distinctive vortex breakdown locations.
Highlights
Fighter aircrafts with high maneuverability, agility and swiftness are highly demanded
If a fighter pilot miss on the first shot, after maneuvering at a small-radius 180o turn and course reversal, the aircraft will be at a lower speed, but the design still allows the aircraft to turn within three seconds and take another shot, with no fear of stall due to vortex breakdown and flow separation
Simulation Results 3.1 CFD Simulation & Canard Vortex Centers of Chengdu J-10 with Fuselage The vortex structures of the canard are displayed in Fig. 5 for α = 10o, 15o, 20o, 25o and 30o using the Q = 2.5 ×
Summary
Fighter aircrafts with high maneuverability, agility and swiftness are highly demanded. Fighter needs significant lift increase and stall delay to postpone vortex breakdown and stall at high AoA. The mechanism of vortex breakdown delay is largely due to the downwash created by the canard vortex in the inner part of the wing, which reduces the local effective AoA, suppressing flow separation and delaying the formation of the wing’s leading-edge vortex (Calderon, D.E et al, 2012) (Mahdi, 2015). Sun et al (Sun, Li, & Zhang, 2013) have conducted examination on double delta fighter, Schutte et al (Schütte, Rein, & Höhler, 2007), have performed numerical simulation of maneuvering aircraft X31, Sahin et al (Sahin, Yayla, Canpolat, & Akilli, 2012) had learned flow structure over the yawed non-slender diamond wing. An integrated to UCAV stability & control estimation X31 had been investigated (Cummings & Schutte, 2010)
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