An Experimental Study on the Unsteady Behavior of a Short Bubble on an Airfoil During Dynamic Stall with Special Reference to the Mechanism of the Stall over Shooteffect

摘要

Unsteady behavior of the reattachment point of a short bubble on a two-dimensional wing of NACA 0012 airfoil section during rapid change of angle of attack was studied by the use of miniature pressure transducers installed in the model for the purpose of detecting the sudden pressure rise at the reattachment point. Tests were made for the range of non-dimensional pitch rate from 0 to 0.25 and Reynolds number from 64,000 to 125,000. The results obtained suggest that the delay of the initiation of the leading edge vortex shedding is, at most, the same order of magnitude as the delay of the movement of the reattachment point. (Author)