The Influence of Unsteady Rotor Response on a Distorted Flow Field

Abstract

The influence of the unsteady rotor response on the shape of stagnation pressure and axial velocity distortions passing through an axial flow rotor are investigated. Experimental data obtained with an isolated rotor in an incompressible, distorted inflow demonstrate that the magnitude of the distortion downstream of the rotor is a strong function of the ratio of the blade spacing s to the distortion wavelength ln. An existing actuator disk analysis based on a quasi-steady model of the rotor response and used extensively to predict the downstream distortion, has been extended to include the unsteady response of the rotor. By examining a series of sinusoidal distortions of varying wavelength, a semi-actuator disk analysis, which includes the unsteady rotor response, is shown to predict the same trend with s/ln as exhibited by the experimental data.