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beginner-hlp pls

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Old   September 29, 2009, 22:52
Default beginner-hlp pls
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sarangarajan
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hi guys i want to set a pressuer of 2 units in movingwall1 and 1 in movingwall .. am getting an error in this could you guys help me with it?

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 1.6 |
| \\ / A nd | Web: http://www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 2 -2 0 0 0 0];

internalField uniform 0;

boundaryField
{
movingWall
{
type fixedValue;
value uniform (1 0 0);
}

movingWall1
{
type fixedValue;
value uniform (2 0 0);
}

fixedWalls
{
type zeroGradient;
}

frontAndBack
{
type empty;
}
}

// ************************************************** *********************** //
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Old   September 30, 2009, 00:40
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Alberto Passalacqua
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Quote:
Originally Posted by sarajags_89 View Post
hi guys i want to set a pressuer of 2 units in movingwall1 and 1 in movingwall .. am getting an error in this could you guys help me with it?

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 1.6 |
| \\ / A nd | Web: http://www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 2 -2 0 0 0 0];

internalField uniform 0;

boundaryField
{
movingWall
{
type fixedValue;
value uniform (1 0 0);
}

movingWall1
{
type fixedValue;
value uniform (2 0 0);
}

fixedWalls
{
type zeroGradient;
}

frontAndBack
{
type empty;
}
}

// ************************************************** *********************** //
A pressure is a scalar, not a vector, so don't use (1 0 0) but simply 1.

However, why do you specify the pressure at a wall, since if you use the no-slip condition, you already specify the velocity, and the pressure should be set to zeroGradient.

Best,
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GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as live DVD/USB, hard drive image and virtual image.
OpenQBMM - An open-source implementation of quadrature-based moment methods
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Old   September 30, 2009, 13:27
Default @ alberto
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sarangarajan
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Thanks for the reply. Actually I am modifying the cavity problem in the tutorial. I am keeping one face as inlet and the other as outlet. So I named one face of the face as movingwall and an opposite face as movingwall1. I then specified pressure difference as well as velocity difference is this right
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Old   September 30, 2009, 13:38
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Alberto Passalacqua
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You should specify velocity at the inlet, where p is set to zeroGradient, and pressure at the outlet, where velocity is set to zeroGradient. Keep in mind you consider incompressible flows.
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OpenQBMM - An open-source implementation of quadrature-based moment methods
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Old   September 30, 2009, 17:09
Default @alberto
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hi.. I understood what you said.. my question is how do i differentiate vectors and scalars when I type them in the editor
hope this is clear

for pressure

movingWall
{
type fixed;
value 0;
}

is this correct?

Last edited by sarajags_89; September 30, 2009 at 18:50.
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Old   September 30, 2009, 19:55
Default
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Alberto Passalacqua
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Quote:
Originally Posted by sarajags_89 View Post
hi.. I understood what you said.. my question is how do i differentiate vectors and scalars when I type them in the editor
hope this is clear

for pressure

movingWall
{
type fixed;
value 0;
}

is this correct?
No it is not correct.

movingWall
{
type fixedValue;
value uniform 0;
}

is the right syntax. This should be clear by all the examples you find in the tutorials.

Best,
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Alberto Passalacqua

GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as live DVD/USB, hard drive image and virtual image.
OpenQBMM - An open-source implementation of quadrature-based moment methods
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Old   September 30, 2009, 19:56
Default
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Alberto Passalacqua
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Quote:
Originally Posted by annoyed View Post
>hi.. I understood what you said..

Please, don't lie at us.

>my question is how do i type vectors scalars

'v' 'e' 'c' 't' 'o' 'r' 's' 's' 'c' 'a' 'l' 'a' 'r' 's'

>what is uniform(0 0 0) mean?..

The mean of uniform(0 0 0) is (0 0 0).

You should check your '.' key. It is typing itself in places, where it makes as little sense as the rest of the questions.
Maybe next time you can save your time, and do not reply at all.
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GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as live DVD/USB, hard drive image and virtual image.
OpenQBMM - An open-source implementation of quadrature-based moment methods
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