Analysis of unsteady vortex sheet in 2-D axial compressor

The flowfield in turbomachinery is characterized by unsteady vortex flow. Contradictorily, the current analysis and design system of axial compressor is based on the spatial structure of the flowfield under the assumption of steady flow. It is understood that one of the methods to investigate the real flow inside the axial compressor is to analyze the temporal-spatial structure of the flowfield. In this paper, an axial compressor stage embedding interlaced rotor and stator rows was simplified into a single blade row, and then further into a 2-D compressor cascade. In this way, the temporal-spatial structure of the unsteady vortex flowfield could be described from the angle of unsteady vortex sheet of the cascade. For illustration, the temporal-spatial structure of the flowfield in cascade was transformed through controlling the evolution of vortex sheet by synthetic jet normal to the suction surface of the cascade. The presented unsteady vortex sheet model could be used as an analysis tool for further research on the temporal-spatial structure of stator/rotor interaction in multistage turbomachinery flowfield.