Turbomachine subassembly comprising a gooseneck of improved configuration, and turbomachine comprising such a subassembly

An aircraft turbomachine subassembly comprising an annular duct which extends concentrically about a longitudinal axis and wherein an air stream flows from upstream to downstream, the annular duct comprising at least one duct portion which defines, for the air stream, a swan neck having an upstream inlet section and a downstream outlet section, the turbomachine subassembly comprising, in said at least one duct portion, a plurality of arms which extend according to a circumferential distribution relative to the longitudinal axis in a spaced manner from each other, each following a radial and axial extension, wherein the aircraft turbomachine subassembly comprises one or several intermediate walls extending between two circumferentially adjacent arms which form a pair of circumferentially adjacent arms among the plurality of circumferentially adjacent arms so as to locally separate, between the two arms of the pair of arms, said at least one annular duct portion into a radially inner portion for an inner portion of the air stream and a radially outer portion further away from the longitudinal axis than the radially inner portion for an outer portion of the air stream.