Numerical Analysis of Transonic Buffet on SC(2)-0518 Airfoil with Trailing Edge Flaps

Abstract

Transonic buffet is an oscillating shock wave phenomenon generated on the upper surface of a wing. A Gurney Flap (GF) has recently been studied as a device that can suppress the transonic buffet. In this study, we numerically analyzed the influences of the GF arrangements on the transonic buffet characteristics, in which the GF is attached at the trailing edge of the wing in the upward or downward vertical directions. When the GF with height of 2%c (where c is the chord length) was attached vertically downwards, the lift coefficient increased by 26% relative to the clean wing case (with no devices attached). In this case while the lift-to-drag ratio decreased by 14%, we succeeded in reducing the buffet amplitude by 35%. On the other hand, attaching the same flap in the upward direction improved the lift-to-drag ratio by 7% compared to the clean case, and succeeded in suppressing transonic buffet.