Aircraft noise, from engines, jets, or air flowing over wings, is a major challenge in aviation. Reducing this noise is not just about comfort; it’s also about meeting strict environmental regulations and improving the quality of life for communities near airports. However, tackling this issue is complex. It requires a deep understanding of how air moves (aerodynamics), how sound behaves (acoustics) and how they interact, as well as the ability to design solutions that reduce noise without compromising the aircraft’s performance.
One of the technologies in this area is the acoustic liner, a structure with tiny orifices backed by a honeycomb structure and a rigid back plate, often seen at the front of jet engines. These liners are designed to absorb sound at specific frequencies, especially the loudest ones. But as aircraft engines evolve to become more fuel-efficient, like the new ultra-high bypass ratio engines, the nature of the noise they produce is changing. These engines generate lower-frequency and more broadband (spread-out) noise, which traditional liners aren’t optimized to handle.
This shift creates a need for new types of liners that can effectively reduce this broader range of noise while maintaining aerodynamic efficiency (i.e. not increasing drag or fuel consumption). However, designing these new liners is difficult, especially since even the behavior of traditional liners isn’t fully understood in all conditions.
The LINING project's goal is to deepen our understanding of how air and sound interact with both conventional and novel liner designs. By combining high-fidelity computer simulations with real-world experiments, the project aims to bring the relevant physics into the design process from the beginning, leading to better, quieter, and more efficient aircraft.
