Development of light-weight, integrated and multifunctional acoustic metamaterials/metasurfaces to reduce noise from next generation aero-engines: modelling and data

Increased air transport has resulted in greater annoyance from aviation noise. The WHO identifies noise as the second biggest environmental public health risk in the EU. Conventional barriers cannot mitigate civil aviation noise. The aim of this work is to attenuate noise at source, designing innovative configurations which are able to absorb, dissipate, and redirect acoustic waves. To achieve this, new light-weight multi-functional acoustic metamaterials and metasurfaces are being investigated to be used inside, at the inlet and at the exhaust of nacelles without adding weight to the aircraft.
Periodicity-enhanced metamaterials and metasurfaces are artificial structures with acoustic properties not found in natural materials. They have already been proven in room acoustics and in traffic noise but they have not been explored for aeronautical applications [1]. This study focusses on designing new metamaterials and metasurfaces, and also on tackling the new challenges of modelling sound propagation and diffraction involving moving sources in moving media [1]. This provides a significant challenge in predicting sound propagation through aero-engines as conventional methods are not applicable. The work presented here considers the development and re-formulation of existing techniques to incorporate the aeroacoustic environment and to validate results with experimental data.