DEFINITION:

1. Internal noise reduction. Active Control. The aim is to decrease the level of noise due to the vibrations of structures with the use of active control algorithms able to take into account different noise sources, i.e. wide band excitations.
2. External noise reduction. Reduction at the source; acoustic absorbing materials (passive and adaptive). Link with ATM and Human Factors (noise perception).

(Source: ACARE Domain 212)

SUBDOMAINS:

1. Active Control algorithms
2. Techniques in relation with actuators and sensors such as piezoelectric or piezoceramic materials, electrostrictive ceramics… and their mechanical modellisation.
3. Automatics and real time systems for the study and for the realisation of controllers
4. Optimisation of the location of patches on the structures
5. Modal identification of structures
6. Knowledge of noise sources and identification of acoustic leaks
7. Acoustic measurements for the validation of Active Control
8. Sources:

8.1. Optimisation of aerodynamic and acoustic performance through new design of fan blade and vanes, advanced propellers (possibly uneven spaced), and helicopter rotors.
8.2. Novel aircraft designs to mask some sources, or to alleviate installation effects (interactions) on noise generation.

9. Acoustic linings:

9.1. New concepts of passive or adaptive materials
9.2. Extensions to high temperatures on the exhaust duct

10. Noise abatement procedures