LOW NOISE FAN ASSEMBLY

摘要

A gas turbine engine rotor assembly such as a fan or compressor includes a plurality of rotor blades spaced axially from a plurality of stator vanes inside an annular duct. The number of vanes is selected for a predetermined number of blades for obtaini ng substantially equal values of a cut-off ratio for at least two blade passing frequency harmonics for reducing spinning mode noise from the duct.