LOW-FREQUENCY ACOUSTIC CENTER BODY

A center plug (206) for attenuating noise in a gas turbine engine (122) includes an inner skin (430), the inner skin (430) having a substantially cylindrical shape and extending along an axial centerline (A); an outer skin (416) positioned radially outside the inner skin (430); a forward bulkhead (450) disposed proximate a forward end of the inner skin (430), the forward bulkhead (450) connected to and extending radially outward from the inner skin (430); an aft bulkhead (452) disposed proximate an aft end of the inner skin (430), the aft bulkhead (452) connected to and extending radially outward from the inner skin (430); and a first resonator cavity (444) disposed within a volume defined by the inner skin (430), the outer skin (416) and the forward bulkhead (450) and the aft bulkhead (452), the first resonator cavity (444) including a first perforated disk (460) extending between the inner skin (430) and the outer skin (416) and forming a first sub-cavity (1) and a second sub-cavity.