US Patent 11639666 Stator with depressions in gaspath wall adjacent leading edges

A fluid machine for an aircraft engine has: first and second walls; a gaspath defined between the first wall and the second wall; a rotor having blades rotatable about the central axis; and a stator having: a row of vanes having airfoils including leading edges, trailing edges, pressure sides and suction sides opposed the pressure sides, and depressions defined in the first wall, the depressions extending from a baseline surface of the first wall away from the second wall, a depression of the depressions located circumferentially between a pressure side of the pressure sides and a suction side of the suction sides, the depression axially overlapping the airfoils and located closer to the suction side than to the pressure side, an upstream end of the depression located closer to a leading edge of the leading edges than to a trailing edge of the trailing edges.