Time-variant aerodynamic measurements in a research compressor

A technique for understanding and controlling unsteady flows, to achieve improvements in turbomachinery design and performance, is described. The instrumentation is detailed, noting the dynamic pressure transducers which are flush mounted on a pair of NACA Series 65 stator vanes. The time-variant wake measurements are obtained with a cross-wire probe located in the rotor-stator axial gap of the flow passage adjacent to the dynamically instrumented airfoils. Data acquisition and analysis are covered. Also undertaken were (1) a qualitative study of the rotor wake velocity profile as a function of both compressor loading and downstream axial distance, (2) a quantitative investigation of the resulting time-variant surface pressures induced on the stator vanes by the upstream generated rotor wakes as they are convected downstream. Attention is also given to wake profile investigation and unsteady pressure differential data-theory correlation.