A broadband noise model for turbulence/annular-cascade interaction

This paper takes the three dimensional lifting surface method into the broadband fan noise prediction theory as a new response function. The stator is modeled as an annular cascade with the purpose of studying the three dimensional effects realistically. Compared with the strip theory widely used in existing analytical broadband fan noise models, the unsteady surface pressure distribution on the stator vanes is calculated under fully three dimensional consideration. The upstream turbulence is described by Liepmann spectrum. The model is verified through comparing the prediction results with previous experiment results. Then the effect of swept vanes is briefly studied. The results show that vane swept effect is greater at low frequencies because of three dimensional effect, compared with high frequencies, at which the swept effect is relatively small.