A system comprising: a turbine comprising: an expansion section configured to expand an exhaust flow in a downstream direction, wherein the expansion section comprises a plurality of stages; a cooling manifold coupled to the turbine, wherein the cooling manifold is configured to direct a cooling flow toward a turbine casing disposed about the plurality of stages of the expansion section; and a diffuser section coupled downstream of the expansion section, wherein the diffuser section is configured to receive the exhaust flow along an exhaust path and an energizing flow along a wall, the diffuser section comprising: the wall comprising an inner surface, wherein the wall is disposed about the exhaust path; and an energizing port disposed in the wall at or downstream of a last stage of the plurality of stages of the expansion section, wherein the energizing port is configured to direct the energizing flow along the inner surface of the wall to energize a boundary layer along the wall, and a first pressure of the energizing flow is greater than a second pressure of the exhaust flow at the energizing port; the energizing port being configured to receive at least a portion of the cooling flow from the cooling manifold as the energizing flow to energise a boundary layer with the cooling flow between a wall and the exhaust gas. a turbine comprising: an expansion section configured to expand an exhaust flow in a downstream direction, wherein the expansion section comprises a plurality of stages; a cooling manifold coupled to the turbine, wherein the cooling manifold is configured to direct a cooling flow toward a turbine casing disposed about the plurality of stages of the expansion section; and a diffuser section coupled downstream of the expansion section, wherein the diffuser section is configured to receive the exhaust flow along an exhaust path and an energizing flow along a wall, the diffuser section comprising: the wall comprising an inner surface, wherein the wall is disposed about the exhaust path; and an energizing port disposed in the wall at or downstream of a last stage of the plurality of stages of the expansion section, wherein the energizing port is configured to direct the energizing flow along the inner surface of the wall to energize a boundary layer along the wall, and a first pressure of the energizing flow is greater than a second pressure of the exhaust flow at the energizing port; the energizing port being configured to receive at least a portion of the cooling flow from the cooling manifold as the energizing flow to energise a boundary layer with the cooling flow between a wall and the exhaust gas. an expansion section configured to expand an exhaust flow in a downstream direction, wherein the expansion section comprises a plurality of stages; a cooling manifold coupled to the turbine, wherein the cooling manifold is configured to direct a cooling flow toward a turbine casing disposed about the plurality of stages of the expansion section; and a diffuser section coupled downstream of the expansion section, wherein the diffuser section is configured to receive the exhaust flow along an exhaust path and an energizing flow along a wall, the diffuser section comprising: the wall comprising an inner surface, wherein the wall is disposed about the exhaust path; and an energizing port disposed in the wall at or downstream of a last stage of the plurality of stages of the expansion section, wherein the energizing port is configured to direct the energizing flow along the inner surface of the wall to energize a boundary layer along the wall, and a first pressure of the energizing flow is greater than a second pressure of the exhaust flow at the energizing port; the energizing port being configured to receive at least a portion of the cooling flow from the cooling manifold as the energizing flow to energise a boundary layer with the cooling flow between a wall and the exhaust gas. the wall comprising an inner surface, wherein the wall is disposed about the exhaust path; and an energizing port disposed in the wall at or downstream of a last stage of the plurality of stages of the expansion section, wherein the energizing port is configured to direct the energizing flow along the inner surface of the wall to energize a boundary layer along the wall, and a first pressure of the energizing flow is greater than a second pressure of the exhaust flow at the energizing port; the energizing port being configured to receive at least a portion of the cooling flow from the cooling manifold as the energizing flow to energise a boundary layer with the cooling flow between a wall and the exhaust gas.