Aircraft propulsion system with acoustically treated propulsor rotating structure

An apparatus for an aircraft, comprising:

• a propulsion system including a propulsor rotating structure and an engine core configured to power rotation of the propulsor rotating structure about an axis;
• the propulsor rotating structure comprising a propulsor rotor, and the propulsor rotor comprising a plurality of propulsor blades arranged circumferentially about the axis;
• and
• the engine core including a flowpath, a compressor section, a combustor section and a turbine section, and the flowpath extending through the compressor section, the combustor section and the turbine section from an inlet into the flowpath to an exhaust from the flowpath;
• wherein a flow boundary of the propulsion system is acoustically treated to attenuate sound generated by operation of the propulsion system along at least
• an upstream section of the flow boundary that is upstream of the plurality of propulsor blades;
• and
• a downstream section of the flow boundary that is downstream of the plurality of propulsor blades and upstream of the inlet into the flowpath.