On a mode-matching technique for sound generation and transmission in a linear cascade of outlet guide vanes

Abstract

The present work is dealing with the analytical modeling of two aspects of stator noise in axial-flow fan and compressor architectures, namely the transmission of acoustic waves through a row of outlet guide vanes, on the one hand, and the sound generation by impingement of the wakes of an upstream rotor on the vane row, on the other hand. In the first case incident acoustic waves are diffracted by a row of stator vanes. In the second one vortical waves are scattered as sound as they interact with the vane row. The same mode-matching technique is applied iteratively at the front-face (leading edge) and at the back-face (trailing-edge) interfaces of the stator for both problems. This unified and quite simple approach is described in the case of a two-dimensional rectilinear-cascade in the paper but its interest is that it can be easily transposed to a three-dimensional annular cascade in cylindrical coordinates. It is validated by comparing with a previously developed Wiener-Hopf model.