Rotor system for an aircraft

A rotor system for an aircraft, comprising:

• a rotor configured to be driven and having multiple rotor blades disposed about an axis of rotation of the rotor substantially radially, wherein a plane perpendicular to axis of rotation, which extends through the rotor blades in a radial direction, forms a rotor plane, and
• a rotor shroud, which surrounds the rotor circumferentially with regard to the axis of rotation and which confines an air duct of the rotor extending in an axial direction of the axis of rotation,
• wherein the rotor shroud forms a hollow structure extending circumferentially with regard to the axis of rotation, wherein the hollow structure has on its circumferential face facing the rotor in the radial direction at least in a section thereof an area permeable to gas, wherein the rotor plane intersects the area permeable to gas, and
• wherein the hollow structure is configured such that acoustic waves of at least one frequency penetrating through the area permeable to gas into the hollow structure are at least partially absorbed by the hollow structure.