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 | | From: | heiko ackermann | | Subject: | Non-linear overlaying of waves in water | | Date: | 23 Jan 2005 09:00:18 -0800 |
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 | Hey,
If I overlay two acoustic waves with different frequencies in water,
and my amplitudes are high enough for linear effects.
There will be four waves, the two wave frequencies and the new two
ones, f1-f2 and f1+f2
Now I want to know if what's about the amplitude of the two new ones.
Will the amplitude change, or will it be the always the same.
In the linear case the beating ampltidue will change, but whats about
the non-linear chase.
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| | From: | Franz Heymann | | Subject: | Re: Non-linear overlaying of waves in water | | Date: | Mon, 24 Jan 2005 07:43:46 +0000 (UTC) |
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"heiko ackermann" wrote in message
news:410fff40.0501230900.4ba5271@posting.google.com...
> Hey,
> If I overlay two acoustic waves with different frequencies in water,
> and my amplitudes are high enough for linear effects.
> There will be four waves, the two wave frequencies and the new two
> ones, f1-f2 and f1+f2
These sum and difference frequencies will not occur if you are
considering a linear system, as you said above here.
>
> Now I want to know if what's about the amplitude of the two new
ones.
> Will the amplitude change, or will it be the always the same.
Play around with an expression of the kind
y = y1*sin(w1*t) + y2*sin(w2*t) + alpha*sin(w1*t)*y2*sin(w2*t)
until you have only a sum of simple sinusiodal oscillations. Alpha
would be indicative of the relative strength of the non-linearity.
> In the linear case the beating ampltidue will change, but whats
about
> the non-linear chase.
Franz
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| | From: | CWatters | | Subject: | Re: Non-linear overlaying of waves in water | | Date: | Sun, 23 Jan 2005 21:56:18 GMT |
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"heiko ackermann" wrote in message
news:410fff40.0501230900.4ba5271@posting.google.com...
> Hey,
> If I overlay two acoustic waves with different frequencies in water,
> and my amplitudes are high enough for linear effects.
> There will be four waves, the two wave frequencies and the new two
> ones, f1-f2 and f1+f2
>
> Now I want to know if what's about the amplitude of the two new ones.
> Will the amplitude change, or will it be the always the same.
>
> In the linear case the beating ampltidue will change, but whats about
> the non-linear chase.
Scroll down this page. Might help..
http://www.kettering.edu/~drussell/Demos/superposition/superposition.html
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| | From: | Duckshit | | Subject: | Re: Non-linear overlaying of waves in water | | Date: | Sun, 23 Jan 2005 11:32:43 -0600 |
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"heiko ackermann" wrote in message
news:410fff40.0501230900.4ba5271@posting.google.com...
> Hey,
> If I overlay two acoustic waves with different frequencies in water,
> and my amplitudes are high enough for linear effects.
> There will be four waves, the two wave frequencies and the new two
> ones, f1-f2 and f1+f2
So it is additive...........
>
> Now I want to know if what's about the amplitude of the two new ones.
> Will the amplitude change, or will it be the always the same.
What happens when you add the waves? Were they the same amplitude to start
with?
>
> In the linear case the beating ampltidue will change, but whats about
> the non-linear chase.
There are many possible types of non-linear cases, so many answers,
typically more harmonics are generated of both f1,f2, and all combinations
of differences of the fundamentals and harmonics. Amplitudes will depend
upon the type of non-linearity.
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