Disclosed is flutter damper including a first cavity having a radially inner side in fluid communication with a flow path, and a second cavity having a radially inner side in fluid communication with a radially outer side of the first cavity, and the flutter damper having an impedance characteristic at one or more target frequencies defined as ftarget=fS,ND+Ω·ND wherein fS,ND is a resonance frequency corresponding to a structural mode of a rotating component, ND is a nodal diameter count of the structural mode, and Ω is a rotational speed of the rotating component, and wherein the flutter damper has the following impedance characteristic at the one or more targeted frequencies R≥2ρc −3ρc≤X≤−0.6ρc wherein R is the real part of the impedance characteristic, X is the imaginary part of the impedance characteristic, ρ is air density, and c is speed of sound.