Rotating blade row oscillating airfoil aerodynamics

A series of experiments is performed in a research compressor to investigate the aerodynamic damping unsteady aerodynamics of a compressor rotor blade row. Specifically, the torsion mode unsteady aerodynamics of the first stage rotor are investigated and quantified, including the effects of oscillation amplitude and steady aerodynamic loading. An experimental influence coefficient technique is implemented in conjunction with a unique torsion mode drive system that provides rotor blade torsion mode oscillations without other motor drive systems. The oscillating blade unsteady pressure influence coefficient data are acquired with dynamic pressure transducers embedded in rotor blades. The resulting rotor blade aerodynamic damping data are then calculated and correlated with linear theory predictions. Oscillation magnitude and steady loading have a significant effect on the equivalent all airfoils oscillating unsteady pressure data, with nonlinear effects evident at high oscillation amplitude.