Engine casing treatment for reducing circumferentially variable distortion

A rotary component for a gas turbine engine defining a central axis extending along an axial direction, a radial direction extending perpendicular to the axial direction, and a circumferential direction perpendicular to both the central axis and the radial direction, the rotary component comprising:

• a plurality of rotor blades operably coupled to a rotating shaft extending along the central axis;
• and
• an outer casing arranged exterior to the plurality of rotor blades in the radial direction,
• wherein the outer casing defines an annular gap between a tip of each of the plurality of rotor blades and the outer casing,
• wherein the outer casing comprises a first portion and a second portion,
• wherein a first feature is formed at the first portion of the outer casing and extends from a first interior radial surface of the outer casing towards a first outer radial surface of the outer casing,
• wherein the first portion of the outer casing has a first casing thickness defined from the first interior radial surface to the first outer radial surface,
• wherein a second feature is formed at a second portion of the outer casing and extends from a second interior radial surface of the outer casing towards a second outer radial surface of the outer casing,
• wherein the second portion is offset at least partially circumferentially or axially from the first portion,
• wherein the second portion of the outer casing has a second casing thickness defined from the second interior radial surface to the second outer radial surface,
• wherein the second casing thickness is different than the first casing thickness,
• wherein the first feature comprises a first circumferential groove extending along the circumferential direction defining a first characteristic at a first circumferential position,
• wherein the second feature comprises a second circumferential groove extending along the circumferential direction defining a second characteristic at a second circumferential position, and
• wherein the first characteristic is different than the second characteristic.