Flow visualization of dynamic stall on an oscillating airfoil
Brydges, Bruce E.
Chandrasekhara, Muguru S.
Platzer, Max F.
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Stroboscopic schlieren photography was used to investigate the efFects of compressibihty, reduced frequency, and amphtude on the dynamic stall of a NACA 0012 airfoil subjected to sinusoidal oscillation. The Mach number was varied from M^o = 0.25 to M^o = 0.45 (corresponding to a Reynolds number variation of Re = 450,000 to Re = 810,000); the reduced frequency was varied from k = 0.025 to k = 0.10. Oscillation amplitudes of am = 5° and am = 10 were compared. Schlieren photographs are presented, which document the dynamic stall vortex formation, convection, and shedding sequence for various experimental conditions. Additionally, a preliminary examination of the flow reattachment process was conducted. Data derived from the photographs indicates that increasing the compressibility causes dynamic stall to occur at lower angles of attack; while, increasing the reduced frequency and/or the oscillation amplitude effectively delays dynamic stall effects to a higher angle of attack. Flow reattachment is sensitive to both Mach number and reduced frequency for low values of these parameters; when either the Mach number or reduced frequency is sufficiently high, the reattachment process stabilizes.
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Hebbar, S.K.; Chandrasekhara, M.S.; Chlebanowski, J.S. (1989-08);Compressibility effects on the dynamic stall of a NACA 0012 airfoil undergoing sinusoidal oscillatory motion were studied using a stroboscopic schlieren system. Schlieren pictures and some quantitative data derived ...
Flow Visualization Studies of the Mach Number Effects on the Dynamic Stall of an Oscillating Airfoil Chandrasekhara, M.S.; Carr, L.W. ;Compressibility effects on dynamic stall of a NACA 0012 airfoil undergoing sinusoidal oscillatory motion were studied using a stroboscopic schlieren system. Schlieren pictures and some quantitative data derived from them ...
Tuncer, Ismail; Walz, Ralf; Platzer, Max F. (American Institute of Aeronautics and Astronautics, Inc., 1998);The dynamic stall boundaries of a NACA 0012 airfoil oscillating in either the pure plunge mode or in the combined pitch and plunge mode is computed using a thin-layer Navier-Stokes solver. Unsteady flowfields are computed ...