Airbus engines

[Craig.]

ok simply put why do airbus engines have that horrible whining sound to them?? and if i am not mistaken dont some boeings use the same engines but without the sound, i dont know what causes it but, with summer fast approaching the red eye flight business has risen here at bristol and as it doesnt have a closing time we are getting flights in 24 hours a day. but the thing is i have to keep my window open as my room turns into a sauna even at night, which mean i am getting woken up every 15 minutes these days.
so can someone please help me understand what causes that awful sound which keeps me awake most the night
Thank you
craig

[Craig.]

no one at all??

[C]

a) something to do with the nacelle design, probably the exhaust nozzle or,

b) you're hearing aerodynamic noise from the airframe, maybe spoilers/ undercarriage???

Charlie

[Craig.]

i know its not the aerodynamics because i have been onboard and even then you could here the sound at fl300 or at least you could on a 320
i think you might be onto something with the nacelle design though

[Rifleman]

Wow you sure gave me a bit of a time on finding some info on this one.......tested my personal resources to come up with a few keywords that would lead me to a search result that I could live with.............here is a partial explanation which may shed some light for you,

Fan noise prediction and control: On modern high-bypass aircraft engines, the fan blade tips rotate supersonically at take-off and produce a sound rich in harmonics, called buzz-saw noise. Predicting the level and frequency content of this noise in the fan duct is a nonlinear acoustic propagation problem which has been reformulated in the frequency domain with promising results. Of specific interest is the effect of absorbent linings. Other work is underway that is aimed at a deeper understanding of the broadband noise generated by a fan. The possibility is also under investigation of modifying the inlet flow field into a fan with a view to providing "active control" of the tonal noise radiated.

But in case this isn't enough, you can go here and see what else interests you on the subject.........http://www.google.ca/search?q=cache:quDyiyqKCFQJ:www.its.berkeley.edu/techtransfer/events/air2002/PDF/IraRushwald.pdf+aircraft+take-off+engine+acoustics&hl=en&ie=UTF-8

[Craig.]

thank you very much for the link:) very useful for the answer:)