resonance

[goodall]

can it occur in curved pipes?

all my memories of it is in straight pipes and the wave diagrams were always in straight pipes, and surely shape a wave would prevent it propitiating in a curved pipe or have i missed something

im thinking about this because most intake manifolds on production cars are curved (i assume to produce resonance) and most exhaust headers are made from curved pipes...
any physicists know anymore

[stiglet]

Yes it can I think.

[GazzaG60]

i think the curve has something to do with the mixing of the fuel and air. as does the rough texture on the inside of the manifold.

[stiglet]

As far as I know it's more or less the same but the curve alters the effective length of the pipe, if that makes sense. I'd imagine if the curve was too severe you would get refelctions too, but fluid mechanics and accoustics is definately not my strong point!

[Sonic]

Surely everything resonates, and its resonance is determined by its size/shape etc?

[stiglet]

Yes but does the air inside the pipe resonate the same if the pipe is curved? As in tuning the length of the pipe for induction at certain RPMs?

[Rusty]

Certainly for things like exhausts, packaging requirements compromise the theoretical calculations. Inlet wise, again, there seems to be quite a lot of use of historically available components and designs... as ever it's a balance between accountancy, physics and space...

[GazzaG60]

also there is the wave issue of bauncing back off the valves. tuning the length and the curve im sure will help here.

[stiglet]

also there is the wave issue of bauncing back off the valves. tuning the length and the curve im sure will help here.

That's the whole point. When you tune the length correctly you get a type of forced induction. Hence variable intake lengths on some cars. I'm just curious to know how the curve affects it all

[goodall]

in the intake system its the 8th over tone is tuned for istr which would mean the curve as used in most oem manifolds would surely be rather restrictive on the wave unless perhaps the curve helps in the intake to make the wave not perfect and thus allow resonance to occur over a broader range, i understand why the intake would be curved so that fit long runners under the bonnet but maybe other reasons to it

but in the exhaust is it not the 1st harmonic that is tuned for and would the bends not be very destructive on the formation of a standing wave, and negate the advantage of tuned length, even though its been shown to give more power

[goodall]

p.s i posted this after an evening drinking celebrating end exams, im amazed reading it here how logical i was

[S2central.net]

I thought everyone on this thread was well ****** up - I don't understand any of it - LOL
8th overtone indeed... very specialist subject this.

[denniselbows]

8th overtone sounds like some you get at the opera. all mumbo jumbo to me too

[S2central.net]

Gimme the undertones anyday - LOL

[nesshead6]

but in the exhaust is it not the 1st harmonic that is tuned for and would the bends not be very destructive on the formation of a standing wave

so how does the onset transient affect the performance of the engine??!?!?! Or does that only influence the timbre of the exhaust sound.... heehee who knows