Fan-OGV broadband noise prediction using a cascade response function Seminar

New engines involve higher bypass-ratio; the jet noise is then reduced and turbomachinery noise can dominate the whole engine signature at cut-back and approach conditions. The tonal components of this noise are well understood and already reduced and controled in current engines architectures. Consequently, broadband fan noise is becoming relatively more significant. Dedicated prediction schemes must be included in the design cycles, as early and as accurately as possible.

An analytical model of the broadband noise produced by both the interaction of ingested turbulence with a fan rotor blades and the rotor-wake impingement on downstream stator vanes is proposed and detailed in a first part. The noise prediction methodology is a
strip-theory approach based on a three-dimensional unsteady blade loading for a rectilinear cascade. The strip theory is then coupled with an acoustic analogy in an annular duct.

In a second a part, the acoustic shielding effect of the rotor on the noise radiated by the stator is investigated.