Numerical Analysis on Unsteady Aerodynamic Characteristics of a Compressor Cascade at Near-Stall Conditions

摘要

Unsteady aerodynamic characteristics of an oscillating cascade composed of DCA blades were numerically studied in high subsonic flow conditions. The focus was placed on the role of separated region on the blade surface for unsteady aerodynamic moment on the blade in pitching oscillation. Two-dimensional Navier-Stokes code with k-ε turbulence model was developed for the present study. In the numerical results for the case without blade oscillation, a separation bubble on the suction surface was properly detected, and the vortex shedding from the blade suction surface was captured in the stall condition. The separation bubble strongly influenced the local unsteady moment of the oscillating blade, though the oscillation instability was not much changed affected. The governing factor of the instability was found to be the unsteady moment induced on the blade pressure surface.