Behavior of Laminar Separation Bubble Formed on NACA 63₁-012

Abstract

Wind tunnel experiments have been made to investigate behaviors of laminar separation bubble formed on a NACA 63₁-012 airfoil at chord Reynolds numbers of Re=1.9×10⁵–3.8×10⁵. Results indicated that a short bubble is formed when the angle of attack α is lower than 10° at Re=1.9×10⁵. The short bubble burst occurs at α=10°. It has been reported that the reattachment point of the short bubble moves upstream as α is increased at higher Reynolds numbers such as at Re=6×10⁶. In this study, however, it is shown that the reattachment point of the short bubble moves downstream as α is increased just before the bubble burst.