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Validation of FLUENT

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Old   August 28, 2010, 00:45
Default Validation of FLUENT
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Destry Marulitua Siagian
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Dear all...

i just run some cases about fluid flow around cylindrical structure..
how can i know my result valid or not?
how can i know this FLUENT valid?




thank you so much...

Gbu
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Old   August 28, 2010, 05:25
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Quote:
Originally Posted by Destry View Post
Dear all...

i just run some cases about fluid flow around cylindrical structure..
how can i know my result valid or not?
how can i know this FLUENT valid?




thank you so much...

Gbu
What type of flow? you may have analytical solution for certain types like laminar or inviscid
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Old   August 28, 2010, 05:36
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Originally Posted by kingjewel1 View Post
What type of flow? you may have analytical solution for certain types like laminar or inviscid

i do analytical solution for inviscid flow...
but from simulation the velocity around the pipe = 0..
but in analytical solution the velocity around pipe = 2*U
U = inflow velocity....

i do the simulation based on FLUENT tutorial....
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Old   August 29, 2010, 02:18
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Quote:
Originally Posted by Destry View Post
i do analytical solution for inviscid flow...
but from simulation the velocity around the pipe = 0..
but in analytical solution the velocity around pipe = 2*U
U = inflow velocity....

i do the simulation based on FLUENT tutorial....

i also do an analytical solution for 1 case from FLUENT tutorial,,,
when i do comparing,,, the result also give a big difference...
especially on the pipe surface..
but when i do comparing above the pipe,,, it gives close result..
is it the limitation of this program?


thx all
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Old   September 1, 2010, 04:21
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Give more information.... and beware of the fact that close to obstacles the velocity lim-s to zero....
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Old   September 1, 2010, 04:46
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Give more information.... and beware of the fact that close to obstacles the velocity lim-s to zero....
inlet velocity= 1 m/s
pipe position in middle of frame...
i also have problem in pressure
also gives a big error (when i comparing to analytical solution)
the analytic solution using superposition of uniform flow+doublet equation...

here i attach velocity contour produce by fluent for my case
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File Type: jpg 1.JPG (47.6 KB, 7 views)
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Old   September 1, 2010, 05:06
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I do not see velocity problems.... check Re and see the flow pattern.... How did you calculate that velocity must be 2*U?!?!? and where it must be so (around where)?
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Old   September 1, 2010, 05:27
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Originally Posted by Philipov View Post
I do not see velocity problems.... check Re and see the flow pattern.... How did you calculate that velocity must be 2*U?!?!? and where it must be so (around where)?
the velocity must be 2*U*sin (tetha) in pipe's surface
where tetha is the angle to the center of pipe....
i calculate them from the superposition of uniform flow+doublet flow...


here i attach the picture again with the angle
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Old   September 1, 2010, 05:41
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On the picture you have resultant velocity ( velocity magnitude) and the formula you are looking for "x"... try to show only velocity on x-axis...
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Old   September 1, 2010, 05:47
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Quote:
Originally Posted by Destry View Post
the velocity must be 2*U*sin (tetha) in pipe's surface
where tetha is the angle to the center of pipe....
i calculate them from the superposition of uniform flow+doublet flow...


here i attach the picture again with the angle
i calculate the resultan also in analytical not only in x direction....

i also attach the equation here....
thx before
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Old   September 1, 2010, 06:12
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I am not sure if you can use these equations for all Re range....
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Old   September 1, 2010, 06:18
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Quote:
Originally Posted by Philipov View Post
I am not sure if you can use these equations for all Re range....


mmmmm


oke,,,
i'll try for smaller Re....
i'll ask u later....


thx for helping
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