an exhaust nozzle for use in a gas turbine engine comprises a flow body for receiving exhaust gas from the turbine engine and includes a leading edge and a trailing edge . the leading edge connects with the gas turbine engine such that the flow body surrounds a centerline of the engine . the trailing edge comprises a serrated portion and a non - serrated portion . the serrated portion is formed from a plurality of tabs for mixing exhaust gas exiting the flow body with gases passing by an exterior of the flow body . the non - serrated portion is positioned along a lower portion of the trailing edge with respect to the engine centerline .