An apparatus, comprising: a nozzle housing having an inlet at a first end and an outlet at a second end, wherein the nozzle housing has a pair of opposing sidewalls and has a front wall and a back wall each extending between the pair of opposing sidewalls; an airflow passage defined by the pair of opposing sidewalls, the front wall and the back wall, wherein the airflow passage has a centerline extending between the inlet and the outlet and has a plurality of cross-sections taken perpendicular to the centerline that collectively define a smooth contour along a length of the airflow passage; and wherein each of the plurality of cross-sections has a thickness (E, C) between the front wall and the back wall that is greater at side edges of both the front wall and the back wall than at the centerline, wherein the thickness (E, C) of each of the plurality of cross-sections both at the side edges of the front wall and the back wall and at the centerline decreases along a length of at least a first portion of the nozzle housing from the inlet toward the outlet, wherein a width of each of the plurality of cross-sections between the pair of opposing sidewalls increases along the length of at least the first portion of the nozzle housing from the inlet toward the outlet, wherein the apparatus further comprises a nozzle extension coupled to the outlet of the nozzle housing and defining a portion of the airflow passage, the nozzle extension having an inlet defining a first area and having an outlet defining a second area that is the same as the first area, wherein a thickness of the inlet of the nozzle extension at the centerline is less than a thickness of the outlet of the nozzle extension, and the thickness of the airflow passage between the front wall and the back wall of the nozzle housing is greater at the side edges of both the front wall and the back wall at the inlet of the nozzle extension than the thickness of the outlet of the nozzle extension, and wherein the outlet of the nozzle extension has a rectangular shape. a nozzle housing having an inlet at a first end and an outlet at a second end, wherein the nozzle housing has a pair of opposing sidewalls and has a front wall and a back wall each extending between the pair of opposing sidewalls; an airflow passage defined by the pair of opposing sidewalls, the front wall and the back wall, wherein the airflow passage has a centerline extending between the inlet and the outlet and has a plurality of cross-sections taken perpendicular to the centerline that collectively define a smooth contour along a length of the airflow passage; and wherein each of the plurality of cross-sections has a thickness (E, C) between the front wall and the back wall that is greater at side edges of both the front wall and the back wall than at the centerline, wherein the thickness (E, C) of each of the plurality of cross-sections both at the side edges of the front wall and the back wall and at the centerline decreases along a length of at least a first portion of the nozzle housing from the inlet toward the outlet, wherein a width of each of the plurality of cross-sections between the pair of opposing sidewalls increases along the length of at least the first portion of the nozzle housing from the inlet toward the outlet, wherein the apparatus further comprises a nozzle extension coupled to the outlet of the nozzle housing and defining a portion of the airflow passage, the nozzle extension having an inlet defining a first area and having an outlet defining a second area that is the same as the first area, wherein a thickness of the inlet of the nozzle extension at the centerline is less than a thickness of the outlet of the nozzle extension, and the thickness of the airflow passage between the front wall and the back wall of the nozzle housing is greater at the side edges of both the front wall and the back wall at the inlet of the nozzle extension than the thickness of the outlet of the nozzle extension, and wherein the outlet of the nozzle extension has a rectangular shape.