Design of materials for noise reduction in aircraft engines

We would like to present in this paper, research that ONERA teams are making in the field of acoustic absorption materials at high temperatures. Some significant results are shown as well as some important findings for future investigation. Research performed in understanding the acoustic and mechanical behaviour of different classes of porous materials and developed processing methods will be described. Our interest was to demonstrate the feasibility of reducing noise produced by aeronautical turbo engines by means of appropriate passive acoustic treatments applied directly to the exhausters.