Abstract: A turbine engine having a turbine section operably connected to an exhaust section, through which an exhaust flowpath is defined. The exhaust section includes a diffuser having a diffuser flowpath. The turbine engine further includes: diffuser walls that define and enclose the diffuser flowpath between an inlet and outlet of the diffuser, the diffuser walls comprising at least one stationary diffuser wall and at least one adjustable diffuser wall; and an actuator connected to the at least one adjustable diffuser wall. The actuator is configured to move the at least one adjustable diffuser wall in relation to the at least one stationary diffuser wall along an axis of movement that causes a modification to a cross-sectional flow area through the diffuser flowpath.