[Destry]

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

[kingjewel1]

Originally Posted by Destry

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

[Destry]

Originally Posted by kingjewel1

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....

[Destry]

Originally Posted by Destry

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

[Philipov]

Give more information.... and beware of the fact that close to obstacles the velocity lim-s to zero....

[Destry]

Originally Posted by Philipov

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

[Philipov]

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)?

[Destry]

Originally Posted by Philipov

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

[Philipov]

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...

[Destry]

Originally Posted by Destry

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

[Philipov]

I am not sure if you can use these equations for all Re range....

[Destry]

Originally Posted by Philipov

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