What happens when hydrogen meets oxygen?

[Lapin Dormant]

Not so practical. The noise being emitted is a broadband frequncy, it's not a nice, simple single frequency. That means whatever is doing it has to have the computing power, plus the output power to be able to mimic what is coming out in real time.

Yes, and the time differntials must be met between pickup, re-creation as inversion, re-emission towards the target.

I have seen it presented on television and it is Capable of Silencing a Helicopters' rotor noise, so I would suspect that even if it sounds (pardon the Pun) complicated, it still can be done, and much more efficiently then some of the other suggestions, less power draining too, much less.

If I recall it properly the lead proponent(?) researcher(?) was from Mc Gill University, in Montreal, Canada.

 

[Danger]

Helicopter rotors, while loud and somewhat variable, still produce a pretty small-spectrum sound compared to turbines. In my experience, at least, turbines are also one hell of a lot louder to start with. In case you're basing your thoughts upon the difference in sound of a jet plane or a helicopter flying overhead rather than being close-up to one, remember that 1) the plane is probably flying a lot higher than the chopper, and 2) the sound of rotors is primarily 'focused' downward whereas the jet exits the back and has far more dispersal before reaching you.

 

[Lapin Dormant]

O.K. but I had seen that it's applicability has range to it, perhaps further study would help, better yet referencing some of the studies, just that I have no time for it, now, so perhaps later, perhaps not.

I seem to recall that It had been stated that it would-could stop the noise from one of those Compressors used to compress air for the air hammers used in construction, also able to supress the Air hammers' noise as well, is that broad enough?

 

[Danger]

is that broad enough?

I've never seen a frequency analysis of a jack hammer/compressor set, but I doubt it very much. Also, they don't have nearly the volume of a decent sized jet. (Note that in the case of a turbine-driven ground vehicle, it's mechanical power from a PTO that drives the wheels. Lots of ducting and expansion chambers and whatnot can be incorporated in the exhaust path because the thing doesn't rely on thrust. That's why the experimental gas turbine buses in Germany and similar are alright for street use.)

 

[Lapin Dormant]

Seen turbines somewhat silenced simply by covering them, so what else is new.

As for the outflow of a jet, it is the noise component that is suppressed, not the outflow component, but you could be qutie right as I have no test facility to experiment upon any of it.

 

[sid_galt]

If you would want to silence it, use a Counteracting sound wave as to annul the emiting wave.

Means use a microphone and computer to pick up on the sound emitted, generate a Counterwave to it, broadcast it back at the originating sound wave, the Two cancel each other, and the noise, disappears.

Practical solution.

Aside from the practicality factor, I don't think this will work at all. The two sound waves will cancel each other only in the region where they interact.

Say if the turbine is at point A and the counteracting sound source at point B, then you would again have noise behind point B. Not to mention that you'll have additional noise beyond point A.

 

[Lapin Dormant]

Aside from the practicality factor, I don't think this will work at all. The two sound waves will cancel each other only in the region where they interact.
Say if the turbine is at point A and the counteracting sound source at point B, then you would again have noise behind point B. Not to mention that you'll have additional noise beyond point A.

No, if you cancel the wave out, it is Gone, no more noise.

I have seen it as applied to cars to replace muffler systems, works VERY well except that, because it is an electrically powered system, it is against 'social norms' due to the nature of Humans inasmuch as they will use disconnect switches and shut the muffler off, and on, and off, and on, all the while enjoying {ignoring} the excessive noise they are making, and it's social impact.

One of the reasons why it never gained ground in that venue, but I can assure you it does work, and really well.

 

[Danger]

As for the outflow of a jet, it is the noise component that is suppressed, not the outflow component,

Sorry, man, but the noise is an integral part of the 'outflow'. This is nothing like the exhaust from a piston engine. It's a very high volume of hot, fast-moving gas coming through a tuned nozzle. There are all sorts of harmonics and mechanical vibrations to deal with. A moderately sized engine (J-34, as used in drag racers) literally shakes the ground for hundreds of feet around it. The thing in Fred's picture is much smaller, but I bet it's probably at least half as noisy.

 

[Ki Man]

seriously, i don't see what's wrong with using cars for now. maybe in the future we will take to the air but until we can put a muffler on a jet or quiet and redisgn helicopters for everyday use, were stuck to the ground. plus, if drunk drivers on the ground are bad, what happens when they have more than 2 dimensions to worry about while driving? do you want drunks crashing into your house in the middle of the night going at 250mph. even if we have virtual sky roads built where drivers don't do much driving we will still face problems like this.

airial vehicles require routine maitenance too. that's going to cost you a lot more than standard gasoline and the occasional oil change.

 

[sid_galt]

No, if you cancel the wave out, it is Gone, no more noise.

The noise will only cancel out at the point where the two waves interfere. Beyond that you'll still hear the noise.

 

[Lapin Dormant]

Silenced myself

Sorry, man, but the noise is an integral part of the 'outflow'. This is nothing like the exhaust from a piston engine. It's a very high volume of hot, fast-moving gas coming through a tuned nozzle. There are all sorts of harmonics and mechanical vibrations to deal with. A moderately sized engine (J-34, as used in drag racers) literally shakes the ground for hundreds of feet around it. The thing in Fred's picture is much smaller, but I bet it's probably at least half as noisy.

Yes I understood that point.

The noise will only cancel out at the point where the two waves interfere. Beyond that you'll still hear the noise.

Interference isn't the goal, cancellation is, then there is no more noise, but, as it is stated above, it would be diffcult, at best, I already knew that, so now, this thread seems to be getting 'hi-jacked' to this topic, so, as to discourage that, I will cease, now.
Thanks

 

[Ki Man]

hopefully testing it this weekend. it depends on how lazy my group members become

 

[Danger]

Good luck, Ki. Keep us updated.

 

[Ki Man]

hmm... before i test this i am going to ask the people something in the general physics section

if i ever become famous, my phrase that people are going to remember after i die is: it all started with a daydream

 

[sid_galt]

Yes I understood that point.
Interference isn't the goal, cancellation is, then there is no more noise, but, as it is stated above, it would be diffcult, at best, I already knew that, so now, this thread seems to be getting 'hi-jacked' to this topic, so, as to discourage that, I will cease, now.
Thanks

According to your theory if two speakers attached to a hi-fi are placed in front of each other, the sound should diminish near completely. But that is not what happens. The sound energy can't disappear into the thin air.

 

[Lapin Dormant]

.. .. ..I will cease now .. .. ..

If you would like to start a new thread, the waves need be equal and Opposite each other, in waveform.

 

[sid_galt]

If you would like to start a new thread, the waves need be equal and Opposite each other, in waveform.

https://www.physicsforums.com/showthread.php?p=787812#post787812"

 

[Ki Man]

okay, definitely testing it this weekend

 

[Danger]

Ki, it appears that the stoned bunny has been banned, so perhaps this thread can stay more or less on topic now. Again, I offer my best wishes for the success of your project.

 

[Ki Man]

me and my group members are hopefully meeting on saterday and going to home depot to buy the proper supplies hopefully unless one of them can't make it. again

ty for the suppor teven if it doesn't work. we are basically researching equalibrums in a sense, but different. if i told you my full idea, youd think i was crazy probably, but it just might work so i'll just keep it secret

 

[Ki Man]

wow i haven't been here in a long time. schools keeping me busy sorry

anyways the testing of it failed. it was designed to be a loophole around themrodynamics/perpetual motion machine. well i came close, but these things can't be done on a 3 dollar budget

anyways now I'm reading up on eintsteins theories and the quest for a theory to the universe so that i can publish some papers on gravity eventually, but don't expect anything until after a few months at least for me to get anything worth done. right now its all research. and i dot have all the time in the world. I'm still in 8th grade so i have time being eaten up by english, math, history, band... this is going to take a looong time

 

[Danger]

Don't sweat it, bud. Einstein was a wee bit older than you and it took him more than a couple of weeks.

 

[Ki Man]

yep. and einstein failed algebra, dropped out of high school, got a job at the bottom of the foodchain in a patent office, then wormed his way into college, and thought up relativity.

 

[Danger]

Yeah, he was a sneaky bastard.