Aircraft engine noise could be SLASHED thanks to revolutionary owl feather study | Science | News | Express.co.uk

Aircraft engines are acknowledged as a significant source of noise, with some planes exceeding 140 decibels during takeoff and landing alone. Noises at such levels can trigger hearing impairment, hypertension, sleep disturbance and even heart disease. But revolutionary new City University of London research suggests mimicking nature may hold the key to reducing aircraft noise in the future.

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Laminar flow for wings.

Just like containing turbulence in water using laminar flow.

Nice.

That article is confusing.
It says that engine noise is the main problem, then talks about having the wing surface looking more like an owl’s feather, but nothing more about engines. For sure the wings make some noise but it’s a lesser component compared to engine noise on both take-off and approach & landing. The extended landing gear also makes more aero noise than the rest of the aeroplane as well.
So I can’t really see any great improvement with that sorry.

Spiny Norman said:

That article is confusing.
It says that engine noise is the main problem, then talks about having the wing surface looking more like an owl’s feather, but nothing more about engines. For sure the wings make some noise but it’s a lesser component compared to engine noise on both take-off and approach & landing. The extended landing gear also makes more aero noise than the rest of the aeroplane as well.
So I can’t really see any great improvement with that sorry.

Yes, agree article is confusing

Tau.Neutrino said:

Spiny Norman said:

That article is confusing.
It says that engine noise is the main problem, then talks about having the wing surface looking more like an owl’s feather, but nothing more about engines. For sure the wings make some noise but it’s a lesser component compared to engine noise on both take-off and approach & landing. The extended landing gear also makes more aero noise than the rest of the aeroplane as well.
So I can’t really see any great improvement with that sorry.

Yes, agree article is confusing

Ah, so this is the owl feather one again.

I wonder how that would affect a sonic boom?

mollwollfumble said:

Tau.Neutrino said:

Spiny Norman said:

That article is confusing.
It says that engine noise is the main problem, then talks about having the wing surface looking more like an owl’s feather, but nothing more about engines. For sure the wings make some noise but it’s a lesser component compared to engine noise on both take-off and approach & landing. The extended landing gear also makes more aero noise than the rest of the aeroplane as well.
So I can’t really see any great improvement with that sorry.

Yes, agree article is confusing

Ah, so this is the owl feather one again.

I wonder how that would affect a sonic boom?

Not much I suspect as most of the over-pressure comes from the tip of the nose and from the tail.

Spiny Norman said:

mollwollfumble said:

Tau.Neutrino said:

Yes, agree article is confusing

Ah, so this is the owl feather one again.

I wonder how that would affect a sonic boom?

Not much I suspect as most of the over-pressure comes from the tip of the nose and from the tail.

That’s right. Got it now.

mollwollfumble said:

Spiny Norman said:

mollwollfumble said:

Ah, so this is the owl feather one again.

I wonder how that would affect a sonic boom?

Not much I suspect as most of the over-pressure comes from the tip of the nose and from the tail.

That’s right. Got it now.

I was thinking about the shock waves from supersonic aircraft and wondered if venting high-pressure air from just behind the very tip of the nose, in a fan pattern, would help disrupt the shock wave so that by the time it got down to the ground it’d have a bit less energy, or it’d just add to the energy and make it louder …. ?

Could aircraft engine noise be suppressed by noise cancelling in the engine itself using oppose sound waves to do the noise cancellation.

Jet engines would have a set of frequencies which are variable so the opposite sound generators would need to be variable and tuned accordingly

Tau.Neutrino said:

Could aircraft engine noise be suppressed by noise cancelling in the engine itself using oppose sound waves to do the noise cancellation.

Jet engines would have a set of frequencies which are variable so the opposite sound generators would need to be variable and tuned accordingly

Some run at 140db so the sound generators would have to be as loud

Tau.Neutrino said:

Tau.Neutrino said:

Could aircraft engine noise be suppressed by noise cancelling in the engine itself using oppose sound waves to do the noise cancellation.

Jet engines would have a set of frequencies which are variable so the opposite sound generators would need to be variable and tuned accordingly

Some run at 140db so the sound generators would have to be as loud

I would also add in acoustic baffles into the engines cones

Tau.Neutrino said:

Could aircraft engine noise be suppressed by noise cancelling in the engine itself using oppose sound waves to do the noise cancellation.

Jet engines would have a set of frequencies which are variable so the opposite sound generators would need to be variable and tuned accordingly

No.

Tau.Neutrino said:

Could aircraft engine noise be suppressed by noise cancelling in the engine itself using oppose sound waves to do the noise cancellation.

Jet engines would have a set of frequencies which are variable so the opposite sound generators would need to be variable and tuned accordingly

Not really. The noise from a jet engine is usually not for the engine itself but is in the mixing of a stream of very hot fast moving air with the surrounding cooler and still air.

Jet aircraft noise of the early 21st century is much less than that of the 1970s or 80s. The way engine manufacturers reduced the noise levels was to increase the bypass ration. Have more air moving through the fan but not the combustion and turbine stages, so that there is more gentle mixing of the exhaust air. Running a smaller and higher pressure combustion and turbine stages helped with fuel economy too, so that is an added bonus. Expect in the future for engines to get even larger diameter.

party_pants said:

Tau.Neutrino said:

Could aircraft engine noise be suppressed by noise cancelling in the engine itself using oppose sound waves to do the noise cancellation.

Jet engines would have a set of frequencies which are variable so the opposite sound generators would need to be variable and tuned accordingly

Not really. The noise from a jet engine is usually not for the engine itself but is in the mixing of a stream of very hot fast moving air with the surrounding cooler and still air.

Jet aircraft noise of the early 21st century is much less than that of the 1970s or 80s. The way engine manufacturers reduced the noise levels was to increase the bypass ration. Have more air moving through the fan but not the combustion and turbine stages, so that there is more gentle mixing of the exhaust air. Running a smaller and higher pressure combustion and turbine stages helped with fuel economy too, so that is an added bonus. Expect in the future for engines to get even larger diameter.

from
ratio

party_pants said:

Tau.Neutrino said:

Could aircraft engine noise be suppressed by noise cancelling in the engine itself using oppose sound waves to do the noise cancellation.

Jet engines would have a set of frequencies which are variable so the opposite sound generators would need to be variable and tuned accordingly

Not really. The noise from a jet engine is usually not for the engine itself but is in the mixing of a stream of very hot fast moving air with the surrounding cooler and still air.

Jet aircraft noise of the early 21st century is much less than that of the 1970s or 80s. The way engine manufacturers reduced the noise levels was to increase the bypass ration. Have more air moving through the fan but not the combustion and turbine stages, so that there is more gentle mixing of the exhaust air. Running a smaller and higher pressure combustion and turbine stages helped with fuel economy too, so that is an added bonus. Expect in the future for engines to get even larger diameter.

Ok, I wonder then if laminar flow suppression could be built into the engines somehow.?

Tau.Neutrino said:

party_pants said:

Tau.Neutrino said:

Could aircraft engine noise be suppressed by noise cancelling in the engine itself using oppose sound waves to do the noise cancellation.

Jet engines would have a set of frequencies which are variable so the opposite sound generators would need to be variable and tuned accordingly

Not really. The noise from a jet engine is usually not for the engine itself but is in the mixing of a stream of very hot fast moving air with the surrounding cooler and still air.

Jet aircraft noise of the early 21st century is much less than that of the 1970s or 80s. The way engine manufacturers reduced the noise levels was to increase the bypass ration. Have more air moving through the fan but not the combustion and turbine stages, so that there is more gentle mixing of the exhaust air. Running a smaller and higher pressure combustion and turbine stages helped with fuel economy too, so that is an added bonus. Expect in the future for engines to get even larger diameter.

Ok, I wonder then if laminar flow suppression could be built into the engines somehow.?

I think the laminar flow stuff might be more aimed at propellers than jet engines. In particular how the air flows around the tips.