Knew that would get your attention John
Whilst listening to the Australian ABC Science show this am, an Australian Prof based in San Diego was taking about the problem they are investigating called "hooting" in large jet engines using lean fuel techniques for low NOx emmision control.
Yup, a combustion instability that causes a combustion flame front oscillation that sounds like a hoot or hum and other organ like notes.
Good ol Google took me here for a fascinating look at the physics.
Hooting
I wonder if it is the same unstable combustion mechanism that causes that hooting sound during most gas turbine start ups.??
We learn something useful every day.
edited to fix fumble fingered incoherence.
