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Old   June 10, 2013, 09:30
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  #21
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Evangelos
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If you convert your case from Fluent where you define the the cyclic boundary conditions .(Needless blockMeshDic)
Quote:
Originally Posted by huxiaoxia View Post
Dear HuyHoang:

Sorry to reply you late. First of all, in constant/polyMesh/blockMeshDic, you have to define the cyclic boundary, e.g
cyclic back
(
(0 2 3 1)
(6 7 9 8)
)
Then , when you define all the initial or boundary conditions under the folder 0, simply use the type cyclic. e.g
back
{
type cyclic;
}

Is it clear for you?
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Old   July 4, 2013, 23:29
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Mohammad
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Hi everyone.
I want to use cyclic (periodic) BC for cavity problem. it sounds simple. I want to use cyclic BC for both P and U (for inlet and outlet). I want to know what I have done is correct or not. Thank you.

This is blockMeshDict:
-------------------------------------------

patches
(
wall topWall
(
(3 7 6 2)
)
wall bottomWall
(
(1 5 4 0)
)
cyclic inout
(
(0 4 7 3)
(2 6 5 1)
)
empty frontAndBack
(
(0 3 2 1)
(4 5 6 7)
)
);

-------------------------------------------
This is my Boundary file:

4
(
topWall
{
type wall;
nFaces 40;
startFace 1540;
}
bottomWall
{
type wall;
nFaces 40;
startFace 1580;
}
inout
{
type cyclic;
nFaces 40;
startFace 1620;
featureCos 0.9;
}
frontAndBack
{
type empty;
nFaces 1600;
startFace 1660;
}
)

--------------------------------------
My 0/U is:
inout
{
type cyclic;
value uniform (0 0 0);
}
---------------------------

Finally 0/P is:
inout
{
type cyclic;
value uniform 0;
}

--------------


Is this correct? I got some result. I get the linear velocity and uniform pressure (Couette Flow). But I am not sure of it.

Is this type of using cyclic correct? what is this "neigbourpathc", "fan" etc..?


Thank you very much.
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Old   July 10, 2013, 04:24
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  #23
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s.rasoul_varedi
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Hi Dear mamad (oshtoli)
i think u need fan BC.
In OF the fan BC prescribes a pressure jump.
Note!The fan boundary condition is working on a cyclic patch.

defined in constant/polyMesh/boundary as
{
type cyclic;
}

and then in the pressure file 0/p:

{
type fan;
patchType cyclic;
f List<scalar> 2(10.0 -1.0);
value uniform 0;
}

The f above is a list of polynomial coefficients in the pressure jump definition

delta p = f_1 + f_2 * v + f_3 * v^2 + ...

Above only f_1 and f_2 is assigned, respectively 10.0 and -1.0.

In 0/U and so on, the ad patch is defined as cyclic.

any quastions are wellcome.
--------
Rasoul
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