Questions tagged [aeroacoustics]

a branch of acoustics that studies noise generation via either turbulent fluid motion or aerodynamic forces interacting with surfaces. Noise generation can also be associated with periodically varying flows

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3 votes
1 answer
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Why are acoustic power loss never taken in account?

At university (I did mechanical engineering) I attended several courses in which energy balance was considered (e.g. thermal machines, electric machines, CFD...). Each time a machine efficiency was ...
temporary_pigeon's user avatar
11 votes
2 answers
3k views

Why is a Lockheed MC-130J Commando II creating such a loud droning sound?

Today I heard a loud droning sound which is really unusual in the area of west London I live in; so I went on ADS-B exchange and it showed a USAF Lockheed MC-130J Commando II flying literally right ...
Daniel K's user avatar
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0 votes
1 answer
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What are the opimum values of Cl during descent?

Statistical Analysis of A320 aircraft shows the Cl values to be as under: cl_value. L is assumed to be 0.5*MaximumLandingWeight of A320 as the Aircraft is about to land. The Units used are: Flight ...
Nooradila Noordin's user avatar
8 votes
2 answers
1k views

How much are noise-related landing costs for a long-range aircraft at Heathrow?

I am trying to estimate the noise-related costs for a long-range platform aircraft (for example, the Boeing 787) at Heathrow Airport. I have found the following table (PDF, page:24) outlining some ...
HotDogCannon's user avatar
69 votes
4 answers
76k views

Why does the Boeing 787 engine nacelle exhaust have such an unusual shape?

Why does the Boeing 787 nacelle have this unique shape at the exhaust: I haven't seen it on any other airplanes, does it serve an aerodynamic purpose or help engine efficiency or is it just to look ...
Lnafziger's user avatar
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