Acoustic Metamaterials
Reza and his team have developed several types of passive and adjustable acoustic metamaterials which are activated and regulated by pneumatic pressure, electromagnetism and heat. We have filed a patent for the concept of acoustical metamaterials. I have used the active mechanism concept for changing the frequency range in which Helmholtz resonators give the best sound absorption. In another study, to improve the acoustical behaviour of porous TEs, a polymeric coating was adopted which was able to extend the frequency range over which there is substantial noise reduction (>5dB) with respect to the original foam. More recently, I investigated the noise reduction performance of AM porous TEs with different unit cell shapes (cubic, hexagonal, diamond) and sizes.
(a) Wing model with additively manufactured porous trailing edge for reduction of noise generation in airplanes and wind turbines [Read paper]
(d) Active acoustical metamaterials based on Helmholtz resonator for adjusting attenuation frequency [Read paper]
(e) Polymeric Coating on Metallic Foams to Control the Aeroacoustic Noise Reduction of Airfoils with Permeable Trailing Edges [Read paper]
