Analysis of unsteady flow in compressor cascade based on modal DMD methods

The reduced-order model based on the modal decomposition method can capture the main characteristics of the compressor. In this part, dynamic mode decomposition (DMD) methods are used to analyze the flow in a high-speed compressor cascade. The methods can extract dynamic information of the flow field. Both the design and off-design conditions (-2°, 0°, 4°) are analyzed. The DMD methods can also obtain the global energy, time coefficient and spatial characteristics of the flow field. DMD mode energy of the characteristic frequency is the highest. The mode with the frequency doubling also has high energy at off-design points. The time coefficient obtained by DMD changes uniformly and eigenvalues are located on the unit circle, which indicates that there is no divergent or convergent mode.