A liner assembly includes a plurality of aligned passages providing a
large open area combined with openings much smaller than a length of the
passages. The plurality of passages are disposed parallel with each other
and include an opening transverse to incident sound waves. The passages
are separated by walls and are blocked at an end distal from the
openings. Sound waves incident on a face of the liner enter the passages
and are dissipated by viscous losses. Sound energy is further dissipated
as thermal energy to the walls of the passages. The long narrow passages
provide the desired visco-thermal losses for sound energy in a broad
frequency range.