Transonic buffet of a supercritical airfoil with trailing-edge flap

1989 ◽  
Vol 26 (5) ◽  
pp. 459-464 ◽  
Author(s):  
B. H. K. Lee ◽  
F. C. Tang
Keyword(s):  
Trailing Edge ◽  
Supercritical Airfoil ◽  
Trailing Edge Flap ◽  
Transonic Buffet

Upper Trailing-Edge Flap for Transonic Buffet Control

2018 ◽  
Vol 55 (1) ◽  
pp. 382-389 ◽  
Author(s):  
Y. Tian ◽  
Z. Li ◽  
P. Q. Liu
Keyword(s):  
Trailing Edge ◽  
Trailing Edge Flap ◽  
Transonic Buffet

scholarly journals Experimental investigation of the transonic buffet cycle on a supercritical airfoil

2021 ◽  
Vol 62 (10) ◽  
Author(s):  
A. D’Aguanno ◽  
F. F. J. Schrijer ◽  
B. W. van Oudheusden
Keyword(s):  
Travelling Waves ◽  
Short Exposure ◽  
Main Peak ◽  
Small Scale ◽  
Trailing Edge ◽  
Cycle Frequency ◽  
Supercritical Airfoil ◽  
Shock Oscillation ◽  
Transonic Buffet ◽  
Good Agreement

Abstract Transonic buffet behaviour of the supercritical airfoil OAT15A was investigated experimentally at flow conditions $$Ma=0.7$$ M a = 0.7 and $$\alpha =3.5^\circ $$ α = 3 . 5 ∘ , using schlieren and particle image velocimetry (PIV). The general behaviour of the buffet cycle was characterised with short-exposure schlieren visualisation and phase-averaged PIV measurements. A spectral analysis showed that the shock oscillation occurs with a dominant contribution at 160 Hz (St = 0.07, in good agreement with the literature) and between 25 and 55 % of the chord of the airfoil. Proper Orthogonal Decomposition (POD) was applied to the PIV data to extract the main modes connected with buffet. It is found that the first three most energetic modes capture around 65 % of the total fluctuating kinetic energy. The first and the third modes have a main frequency peak at 160 Hz and are well representing the separated area and the shock oscillation. The second mode was, instead, associated with an asymmetrical behaviour of the separated area and of the shear layer and displays a main peak at 320 Hz, being double the main buffet cycle frequency. Finally, it was shown that by using the 11 most energetic POD modes, an accurate reduced-order model (ROM) is obtained, which when subtracted from the instantaneous velocity fields allows the visualisation of the small-scale structures present in the flow, such as the upstream travelling waves (UTWs) and the vortex shedding in the separated area near the trailing edge. The analysis allowed to estimate the velocity of the UTWs, obtaining values in good agreement with the literature. In contrast, the analysis of the vortex dynamics in the trailing edge area revealed that vortices shed at the shock foot, which convect downstream in an area detached from the airfoil surface, cannot be considered responsible for the creation of UTWs in view of the mismatch in frequency of the two phenomena. Graphic abstract

Performance enhancement evaluation of an actuated trailing edge flap

2001 ◽  
Vol 105 (1049) ◽  
pp. 391-399 ◽  
Author(s):  
W. Chan ◽  
A. Brocklehurst
Keyword(s):  
Adverse Effect ◽  
Performance Enhancement ◽  
Optimal Configuration ◽  
Analytical Evaluation ◽  
Trailing Edge ◽  
Design Constraints ◽  
Flight Condition ◽  
Trailing Edge Flap

Abstract An analytical evaluation of the performance enhancement due to a servo-actuated trailing edge flap was carried out using the coupled rotor-fuselage model (CRFM). The performance enhancement from a trailing edge flap is achieved by introducing effective camber around the azimuth for a nominal aerofoil. An investigation on the best combination of flap parameters, namely the span, position, chord and deflection was carried out in order to identify an optimal configuration within given design constraints. The effects on vibratory control loads over a range of speed for a flap of 10% span, 20% chord, actuated at once per rev has expanded the retreating blade envelope for a Lynx aircraft by some 20kt. The flap hinge load was also examined and it was found not to be excessive. It was also confirmed that an actuated trailing edge flap does not have adverse effect on the pilot's control inputs to trim to a particular flight condition. This paper will discuss the aerodynamic enhancements derived from the application of the trailing edge flap and present conclusions drawn from this study.

Sign in / Sign up

Export Citation Format

Share Document