Turbofan engine and method of reducing air flow separation therein

An aircraft comprising:

• a fuselage;
• a wing structure coupled to said fuselage;
• and
• a turbofan engine coupled to at least one of said fuselage and said wing structure, said turbofan engine comprising:
• a nacelle housing comprising a radially outer wall and a radially inner wall that defines an interior cavity within said nacelle housing, wherein said nacelle housing further comprises:
• a plurality of first openings defined in said radially inner wall for channeling flow of air therethrough and an opening defined in the radially outer wall;
• an acoustic liner positioned between said radially outer wall and said radially inner wall, wherein the acoustic liner comprises:
• a honeycomb structure coupled to said, radially inner wall, wherein the honeycomb structure comprises one or more channels defined therein that at least partially define a flow passage;
• and
• a face sheet coupled to the honeycomb structure on an opposing side thereof from said radially inner wall, wherein the face sheet comprises a plurality of second openings defined therein;
• a fan assembly positioned at least partially within said interior cavity, wherein said flow passage is defined between said radially outer wall and said radially inner wall for channeling the flow of air therethrough, said flow passage configured to couple a portion of said interior cavity upstream from said fan assembly in flow communication with an ambient environment exterior from said radially outer wall, wherein the opening in the radially outer wall, the plurality of second openings, the respective one or more channels, and the respective first openings are coupled in a serial flow relationship to enable the flow of air;
• and
• said nacelle housing further comprises an actuating door coupled to said radially outer wall of said nacelle housing, said actuating door selectively positioned between an open position and a closed position.

A method of reducing air flow separation in a turbofan engine, said method comprising:

• defining a flow passage between a radially outer wall and a radially inner wall of a nacelle housing of the turbofan engine, wherein the flow passage is configured to couple a portion of an interior cavity of the nacelle housing upstream from a fan assembly in flow communication with an ambient environment exterior from the radially outer wall, wherein said nacelle housing comprises a plurality of first openings defined in said radially inner wall and an opening defined in the radially outer wall, an acoustic liner positioned between said radially outer wall and said radially inner wall, wherein the acoustic liner comprises a honeycomb structure coupled to said radially inner wall, wherein the honeycomb structure comprises one or more channels and a face sheet coupled to the honeycomb structure on an opposing side thereof from said radially inner wall, wherein the face sheet comprises a plurality of second openings defined therein;
• channeling a flow of air between the interior cavity and the ambient environment, wherein the opening in the radially outer wall, the plurality of second openings, the respective one or more channels, and the respective first openings are coupled in a serial flow relationship to enable the flow of air;
• and
• selectively positioning an actuating door defined in the radially outer wall between an open position and a closed position, such that the flow of air is selectively channeled through the flow passage.