Until now, engineers designing next-generation electric aircraft engines could measure how loud these engines were, but they couldn’t explain why the noise felt unpleasant to human ears. To solve this dilemma, the study authors focused on BLI engines.
These engines are built to swallow the slow, messy layer of air that clings to the aircraft’s body during flight. This design helps improve efficiency and reduce drag. However, the downside is that it pulls in turbulent air, which ends up making noise.
The researchers wanted to find out exactly how this disturbed airflow leads to sound, and more importantly, why that sound feels so annoying to people. They set up a high-tech wind tunnel experiment to mimic real flying conditions.