On a mode-matching technique for sound generation and transmission in a three-dimensional annular cascade of outlet guide vanes
Résumé
The present work deals 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 perturbations are scattered as sound as they interact with the vane row. This paper extends an existing analytical model of the aeroacoustic behaviour of a two-dimensional rectilinear cascade to a three-dimensional ducted annular cascade in cylindrical coordinates.
The mode-matching technique used in this model is a simple and uniformly valid approach to address turbomachinery noise issues, avoiding the need to resort to classical strip-theory approaches.