Variable area exhaust nozzle system and method for control thereof

A method of operating a variable exhaust nozzle for a gas turbine engine defining an axial direction, the variable exhaust nozzle including a shroud assembly comprising a fixed shroud and an adjustable cowl mechanically coupled to the fixed shroud and being movable along the axial direction, an adjustable plug slidably positioned within the fixed shroud and being movable along the axial direction, and a nozzle adjustment assembly for selectively positioning at least one of the adjustable cowl or the adjustable plug, wherein the variable exhaust nozzle defines an actual area ratio equivalent to a nozzle exit area over a nozzle throat area, wherein the adjustable cowl is immediately adjacent an aft end of the fixed shroud in a retracted position and spaced apart along the axial direction to define a radial bypass passage between the aft end of the fixed shroud and a forward end of the adjustable cowl when the adjustable cowl is in an extended position, the method comprising:

• receiving data indicative of an operating speed of the gas turbine engine;
• determining a target area ratio based at least in part on received data indicative of the operating speed of the gas turbine engine;
• and
• operating the nozzle adjustment assembly to selectively adjust the adjustable cowl such that the actual area ratio is substantially equivalent to the target area ratio,
• wherein operating the nozzle adjustment assembly to selectively adjust the adjustable cowl comprises spacing apart the adjustable cowl from the fixed shroud along the axial direction to define the radial bypass passage.