| Topic: |
Science > Physics |
| User: |
"" |
| Date: |
02 Apr 2006 10:28:20 PM |
| Object: |
Models or Reality |
I'm a freshman physics student, and I'm wondering whether the Newtonian
model for the flow of fluid(f = -(eta) gradv A)(eta stands for
viscosity) is just a model or a fact. Even my teacher doesn't know any
experiments lay proof on this theory.
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| User: "Martin Hogbin" |
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| Title: Re: Models or Reality |
03 Apr 2006 01:35:10 PM |
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<caofang0605@sina.com> wrote in message news:1144034900.064896.45420@v46g2000cwv.googlegroups.com...
I'm a freshman physics student, and I'm wondering whether the Newtonian
model for the flow of fluid(f = -(eta) gradv A)(eta stands for
viscosity) is just a model or a fact.
Can you tell us what the difference is?
Even my teacher doesn't know any
experiments lay proof on this theory.
Experiments can never prove a theory.
Martin Hogbin
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| User: "Mike" |
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| Title: Re: Models or Reality |
03 Apr 2006 05:17:07 PM |
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wrote:
I'm a freshman physics student, and I'm wondering whether the Newtonian
model for the flow of fluid(f = -(eta) gradv A)(eta stands for
viscosity) is just a model or a fact. Even my teacher doesn't know any
experiments lay proof on this theory.
The perfect sphere is a model of earth, which is a fact. This model is
good for some jobs, very bad for others. In your case, the newtonian
model is very bad model for use in a chocolate factory, the fact being
liquid chocolate is a non-newtonian fluid.
F = dp/dt is a model you cannot actually develop an experiment for,
unless you can find an inertial reference frame. That is really hard.
But it works with good accuracy as a model.
Remember experiments can only falsify a model. Never prove it correct.
Mike
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| User: "" |
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| Title: Re: Models or Reality |
03 Apr 2006 06:51:06 AM |
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It's a realtively simple model for laminar flow (which is also a
model). There are many more, e.g. for extreme fluids (mud, protein
suspensions, mayonaise) and flow situations. But many fluids conform to
it, most importantly: water. Check out the book (from the top of my
head) "Transport phenomena" by Byron Bird. Very good book for the
interested physics student. Stay interested. Cheers, Bart
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