New Noise Type Found in Supersonic Jets During Afterburner Use

What is it about?

This research studied the noise produced by high-performance military jets like the F-22 and F-18E when their afterburners are on. At these extreme speeds and temperatures, jet exhaust behaves differently than in laboratory tests. The study identified a new kind of low-frequency noise that appears only in these conditions. Traditional jet noise comes from turbulent air mixing in the exhaust. However, at very high temperatures, another process—called supersonic instability—creates powerful sound waves that spread at different angles. The study compared data from lab experiments, field recordings, and mathematical models to confirm this new noise source. This low-frequency noise, which includes infrasound (below human hearing), becomes dominant at certain angles behind the aircraft. It may explain why jets using afterburners sound deeper and more intense than expected and could have human and environmental effects beyond normal aircraft noise.

Featured Image

Photo by Jonathan Ridley on Unsplash

Photo by Jonathan Ridley on Unsplash

Why is it important?

Understanding this new noise component matters for both science and public health. Traditional noise-control strategies were designed for turbulence-based noise, but this new supersonic instability noise behaves differently and travels farther. Because it includes strong infrasound, it can cause vibrations or body-cavity resonance that affect people working near aircraft—especially on flight decks or near air bases. The discovery could lead to better jet-engine designs that reduce harmful low-frequency sound without reducing engine performance. The findings also help scientists bridge the gap between small-scale laboratory models and real-world aircraft performance, showing that full-size jets can generate entirely new acoustic phenomena. Recognizing and understanding this new sound type could improve hearing protection, noise regulation, and future aircraft development, making aviation both safer for personnel and quieter for communities near airfields. Key takeaways: 1. High-performance jets at afterburner speeds produce a new low-frequency noise not seen in laboratory experiments. 2. This noise comes from a supersonic instability in jet exhaust flow, not from normal turbulence or shock noise. 3. The new sound is strongest behind the aircraft (over 135° inlet angle) and includes powerful infrasound frequencies. 4. Infrasound can cause body resonance, raising health concerns for nearby workers or residents. 5. Understanding this mechanism could help design quieter, safer supersonic engines and improve noise-control strategies for future aircraft.