Abstract: Disclosed is a rotor system for an aircraft including a rotor having multiple rotor blades disposed about an axis of rotation of the rotor substantially radially. A plane perpendicular to the axis of rotation, which extends through the rotor blades in a radial direction, forms a rotor plane. A rotor shroud surrounds the rotor circumferentially with regard to the axis of rotation, confines an air duct of the rotor extending in an axial direction of the axis of rotation, and forms a hollow structure extending circumferentially with regard to the axis of rotation. The hollow structure has on its circumferential face facing the rotor in the radial direction an area permeable to gas. The rotor plane intersects the area, and the hollow structure is configured to at least partially absorb acoustic waves of at least one frequency penetrating through the area.

Abstract: A sound absorber comprising a base body and a tongue (24). The base body has a bottom plate, a wall enclosing the bottom plate and an opening enabling the entry of air into the base body. The tongue has a fixed end, a free end and a central portion disposed between the fixed and the free end. The free end of the tongue is spaced from the wall and the bottom plate, and the central portion of the tongue is disposed to extend at least partially straight along a width direction. Furthermore, a sound absorber assembly can include at least two sound absorbers, and an engine, in particular, for an aircraft, comprising such a sound absorber and/or such a sound absorber assembly.

Abstract: An aircraft jet engine includes an exhaust-gas nozzle having a device configured to blow out an exhaust gas in a pulsating manner into an exhaust-gas stream so as to reduce noise. The exhaust-gas nozzle includes openings distributed along a circumference of the exhaust-gas nozzle and disposed upstream from a nozzle outlet. The openings communicate with the device.

Abstract: A sound absorber comprising a base body and a tongue (24). The base body has a bottom plate, a wall enclosing the bottom plate and an opening enabling the entry of air into the base body. The tongue has a fixed end, a free end and a central portion disposed between the fixed and the free end. The free end of the tongue is spaced from the wall and the bottom plate, and the central portion of the tongue is disposed to extend at least partially straight along a width direction. Furthermore, a sound absorber assembly can include at least two sound absorbers, and an engine, in particular, for an aircraft, comprising such a sound absorber and/or such a sound absorber assembly.

Abstract: An aircraft jet engine includes an exhaust-gas nozzle having a device configured to blow out an exhaust gas in a pulsating manner into an exhaust-gas stream so as to reduce noise. The exhaust-gas nozzle includes openings distributed along a circumference of the exhaust-gas nozzle and disposed upstream from a nozzle outlet. The openings communicate with the device.