DPIV study of near-stall wake-rotor interactions in a transonic compressor

Wake-rotor interactions at near-stall conditions are studied using digital particle image velocimetry (DPIV) in a transonic compressor at the Compressor Aero Research Lab (CARL) at Wright-Patterson Air Force Base. The wake generators (WGs) are designed to simulate wakes of highly loaded stators without producing flow swirl. Flow visualization, instantaneous, and average velocity field data are presented for near-stall compressor operating conditions. These results describe the interaction of the wake shed from the upstream WG with the downstream potential field of the rotor leading edge for two axial spacings at 75 and 90% span. The advantage of ensemble averaging is demonstrated when operating at challenging conditions such as near-stall, which poses special difficulties in obtaining DPIV data. Ensemble averaging, which is possible because of a natural phase locking provided by the blade potential field, allows robust statistics.