The project focused  on the reduction of the noise propagating outside turbofan nacelles, exploiting the unconventional properties of acoustic metamaterials to modify noise scattering patterns. The experiments were mainly focused on two general aeroacoustic applications, each represented by a simple test rig.  A flat plate test rig for the representation of  the acoustic scattering problems from geometrically discontinuous  surfaces (such as noise scattering from above wing mounted engines) and a duct rig to represent the noise radiation problems related to duct acoustics (such as noise radiation from an engine nacelle) were designed, manufactured and tested. The results have shown the potential benefits of employing metasurfaces as surface treatments.