BTW a good example of a Helmholtz resonator is blowing
across the opening of a Coke bottle.
Paul Lamar
I suspect if you apply the Helmholtz resonator principle to an intake
manifold properly you may reduce the length of intake pipe necessary
to tune the engine. Since the length required is shorter the
internal skin friction drag is also less. At least I think this
is what Porsche is up to. I could be totally wrong.
http://www.phys.unsw.edu.au/~jw/Helmholtz.html
Hi Paul,
are you suggesting using the resonator as a pressure accumulator,
analogous to a capacitor in a tuned radio circuit?
Must it be mounted with the inlet 90 deg to the airflow?
It follows from your graphs showing tuned length as related to varying
diameter of inlet tract. Or, we could mount one on the end of a plenum
to resonate with all the inlet pulses, like a sophisticated air spring
that resonates with the inlet pulses; like a vibrator
Perhaps I am describing two different implements here, one a capacitor,
and the other the H resonator. I imagine each inlet would have to have
its own H resonator, set at 90 deg to the flow.
If we could shorten the inlet tract, this could be a useful gadget.
BR, Dave McC
I would need a Phd in acoustics to begin to know how
to apply the principle. I don't have the foggiest :)
Maybe with a $1,000,000 budget, a dyno and five years I might
be able to come up with something :)
Paul Lamar ...No rotor no motor.
I was looking through a collection of technical papers on turbocharger
looking for back pressure data that Gordon was interested in.
I came across these papers that deal with Helmholtz resonator
intake manifold design in piston engines. As Dave M says we could
shorten the tubes if we had the right volume of chamber on the end
of them. This is a light at the end of a tunnel.
That would solve a lot of installation problems with
low cowls.
Paul Lamar ...No rotor no motor.
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