Analytical assessment of stator sweep and lean in reducing rotor-stator tone noise

Abstract

A theoretical model of fan noise is utilized to quantify the benefits of stator vane sweep and lean in reducing rotor-stator interaction tone noise. A simple, kinematically based, argument is given to elucidate the mechanism of noise reduction. Results from a series of parametric calculations are then presented. Prom these results the optimal vane sweep and lean combination for minimizing tone noise emissions from a representative high bypass ratio fan stage are determined.