RESEARCH ON ROTATING STALL IN AXIAL FLOW COMPRESSORS PART Ⅰ. On Lift Hysteresis at Maximum Lift Including Effect of Camber

摘要

A theoretical investigation is conducted on the effect), of airfoil camber on the magnitude of lift hysteresis at maximum 11ft generated by unsteady boundary-layer phenomena. The effect is demonstrated by comparing the lift hysteresis calculated for an 8-1/2％ cambered 6:1 elliptic cylinder oscillating in a plunging mode about maximum lift with that for an encumbered 6:1 elliptic cylinder oscillating in the same mode. In both cases the lift hysteresis loop is generated in a counterclockwise sense. It is found that the effect of camber is to reduce the magnitude of the hysteresis by 40％. This suggests a possible means for controlling the mag¬nitude of this type of lift hysteresis.nCalculations for an encumbered elliptic cylinder in pitching oscil¬lation about maximum lift indicate only a small difference in the magnitude of lift hysteresis from the plunging mode.