Transonic buffet control by rearward Buffet Breather on supercritical airfoil and wing

Abstract

The transonic buffet over large aircraft wings seriously affects flight safety and ride quality, thus it has been a focus issue for researchers to control transonic buffet through active or passive means. With traditional supercritical airfoil and wing, shock foot bubble and trailing edge separation usually exist in the pre-buffet conditions. The merging of the shock foot bubble and trailing edge separation is associated with buffet onset. In order to prevent shock foot bubble from merging with the trailing edge separation, this paper presents a method to alleviate the transonic buffet by applying the Buffet Breather, which is made of a punched hole near the trailing edge at the RAE2822 airfoil and Wing1 supercritical wing published by Drag Prediction Workshop-III, respectively. The buffet characteristics of the airfoil and wing with and without the Buffet Breather are analyzed with Unsteady Reynolds Averaged Navier-Stokes method. The results show that the Buffet Breather can not only eliminate the buffet phenomenon under two-dimensional condition, but also weaken the pressure oscillation on the wing. In terms of the static aerodynamic characteristics, the Buffet Breather will reduce the lift coefficient under lower angle of attack and deteriorate the lift-to-drag ratio. In the actual application, a control valve can be considered to be installed, to open and close the Buffet Breather in order to achieve the best control effect.