Contribution
Acoustic Metamaterials for electric-Vertical-Take-Off-and-Landing aircrafts
* Presenting author
Abstract:
Urban air mobility vehicles represent a cutting-edge innovation in modern aviation, potentially revolutionizing future mobility. Utilizing electric-Vertical-Take-Off-and-Landing aircrafts (eVTOLs) can significantly lower carbon emissions, improve the transportation infrastructure efficiency, and reduce ground traffic congestion. However, the rise in air traffic in densely populated urban areas raises safety concerns and increases noise pollution, making public acceptance critical for expanding this emerging market. The propulsion technologies for eVTOLs are open-rotor designs and ducted fans, for which specific sound absorption strategies exist. Ducted fans primarily rely on acoustic liners. Traditional noise absorption systems for ducted fan systems in eVTOLs based on the Helmholtz-resonator principle must be revised due to evolving technologies and additional requirements for volume, mass, and acoustics. Therefore, improved acoustical liners are required to decrease emissions and satisfy public acceptance and certification requirements. As a result, we explore innovative noise reduction methods using acoustic metamaterials for ducted fans. This article outlines the requirements and modeling approaches for acoustic metamaterials, particularly under grazing flow conditions, including filtering concepts to select compact, lightweight, and cost-effective designs. Additionally, it discusses the challenges associated with creating digital twins of acoustic systems facilitating next-generation sound-absorbing concepts.