Turbulence and Unsteadiness Measurements Downstream of a Moving Blade Row

Turbulence and unsteadiness levels downstream of an axial-flow compressor rotor have been measured using an ensemble-averaging technique. Free-stream turbulence levels are lowest near the compressor design-point, and increase with decreasing flow coefficient as the compressor nears the stalled condition. The unsteady stator incidence angles have been found to have a peak-to-peak variation of between 12 deg and 15 deg for all flow coefficients tested. These observations have been confirmed qualitatively by hot-wire-anemometer spectral measurements.