Amplitude effects on dynamic stall of an oscillating airfoilAmplitude effects on dynamic stall of an oscillating airfoil in locally transonic flow were studied using stroboscopic schlieren flow visualization. The dynamic stall vortex was photographed for various conditions and its properties were documented. Results show a pronounced effect of the amplitude of oscillation. The airfoil flow can sustain the larger amplitudes with the vortex retained on the surface and thus, produce dynamic lift to higher angles of attack at higher amplitudes. A possible explanation for this is offered in terms of the vorticity generation due to surface acceleration and local streamwise pressure gradient. Also, for the first time a shock has been photographed on the airfoil upper surface and some of its characteristics are discussed.
Document ID
19900032870
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Chandrasekhara, M. S. (U.S.Navy-NASA Joint Institute of Aeronautics Monterey, CA, United States)
Brydges, B. E. (NASA Ames Research Center Moffett Field, CA, United States)