A gas turbine engine includes an engine core having a compressor, a combustor fluidly connected to the compressor, and a turbine fluidly connected to the combustor. A core nacelle is disposed radially outward of the engine core. A cavity is disposed between an inner surface of the core nacelle and an outer surface of the engine core. The cavity includes a vent disposed at an aft end. The vent includes at least one flap configured to be maintained in an unrestricted position and in a restricted position. An actuator is configured to control the position of the at least one flap.