Flutter characteristics of thin airfoils in pitching oscillation. 1st report. The attack angle where the separation bubble moves on the airfoil surface during oscillation.

Abstract

The airfoil used here is NACA 64 A 006 which shows the typical separation pattern of the so-called thin airfoil stall. Unsteady pressure distributions around the airfoil are measured and the relation between unsteady flow behaviour accompanied by a separation bubble and the local energy transfer along the chord are made clear for the pitching oscillation around the mid-chord in the case of an attack angle where the separation bubble moves on the airfoil surface.