Patent ID: 8820088

Claim:
A nacelle assembly for a gas turbine engine comprising: a core nacelle defined about an engine centerline axis; a fan nacelle mounted at least partially around said core nacelle, the core nacelle and fan nacelle defining a fan bypass flow path; and a variable area fan nozzle in communication with said fan bypass flow path, said variable area fan nozzle having a first fan nacelle section and a second fan nacelle section downstream of said first fan nacelle section, said first fan nacelle section and said second fan nacelle section axially movable relative to one another to define an auxiliary port to vary a fan nozzle exit area and adjust fan bypass airflow, said auxiliary port defined between said first fan nacelle section and said second fan nacelle section, said first fan nacelle section comprises a first acoustic system comprising a first acoustic absorbing-material having a first acoustic impedance configured to attenuate a noise characterized by a leading edge of said second fan nacelle section, said first acoustic system disposed at a trailing edge of said first fan nacelle section, said second fan nacelle section comprises a second acoustic system comprising a second absorbing-material having a second acoustic impedance, said first acoustic system extends axially a first length along said first fan nacelle section and said second acoustic system extends axially a second length along said second fan nacelle section, said first length and said second length being substantially equal to each other.