Experimental investigations of unsteady flow in axial compressors

Different types of unsteady flow phenomena in axial compressors have been investigated experimentally with modern and newly developed measuring and testing techniques. In normal operation the instationary flow field between blade rows is measured with different hot-film probes of the split-film type. The evaluation yields turbulence components in three spatial directions and two Reynolds-stress terms. The interaction of stator blade wakes with moving rotor blades is investigated. The initiation, formation and extension of rotating stall in a six-stage model compressor is investigated with a newly developed now-probe technique. Detailed data of the flow and pressure field in a stall cell have been acquired.