Control of transonic buffet by trailing-edge buffet breather

In transonic flight, the phenomenon of transonic buffet arises due to the shock-wave/boundary-layer interaction. To mitigate the effects of transonic buffet while maintaining the lift-drag ratio, a passive buffet control approach utilizing a trailing-edge buffet breather is proposed, based on an analysis of the pressure distribution on a supercritical airfoil. The control effect of the trailing-edge buffet breather and its correlation with breather width, outlet position, and freestream Mach number are analyzed with the unsteady Reynolds-averaged Navier–Stokes (URANS) method on the OAT15A airfoil. Findings suggest that the separation flow behind the shock wave on the suction side of the airfoil is isolated from the separation region at the trailing edge by the buffet breather, impeding the fusion and interaction of these flows and thereby suppressing the transonic buffet. The control effectiveness of the buffet breather can be substantial when the outlet is positioned appropriately downstream of the shock wave. A wider breather width results in a stronger jet intensity, improving control of flow field unsteadiness but with a trade-off of increased lift loss. Furthermore, the control method exhibits efficacy at various Mach numbers, with minimal impact on lift-drag characteristics.