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Linear Velocity Inlet Boundary Condition in Openfoam

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Old   February 26, 2016, 18:11
Question Linear Velocity Inlet Boundary Condition in Openfoam
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Shahil
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I am analyzing turbulent flow over a flat plate and I am trying to specifying inlet velocity as U = Sx*y; where y is the wall-normal co-ordinate and Sx is shear rate, the value I calculated as 11800.
In boundary condition folder for U, I tried specifying linear inlet velocity as follows:

inlet
{
type uniformValue;
uniformValue polynomial
(
( ( 11800 0 0 ) ( 1 0 0 ) )
);
}
The solver is showing following error.

file: /air/U.boundaryField.inlet from line 31 to line 32.

From function fvPatchField<Type>::New(const fvPatch&, const DimensionedField<Type, volMesh>&, const dictionary&)
in file /home/lab/OpenFOAM/OpenFOAM-2.3.x/src/finiteVolume/lnInclude/fvPatchFieldNew.C at line 143.

FOAM exiting


Please give your suggestions.


Please help.
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Old   February 27, 2016, 03:00
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Bloerb will become famous soon enough
polynomial works in the following way:

Code:
uniformValue     polynomial // y = 0.1 + 1.3x^2 + 2.7x^3       
(       
    (0.1     0)       
    (1.3   2.0)       
    (2.7   3.0)       
);
for a vector it is therefore

Code:
uniformValue     polynomial // y = 0.1 + 1.3x^2 + 2.7x^3       
(       
    (0.1     (0 0 0))       
    (1.3   (0 0 2.0))       
    (2.7   (0 0 3.0))       
);
this is a time varying boundary condition that assignes a uniform value that is interpolated using the given polynomial. I suppose you want a boundary condition that gives you such a velocity profile
.../
../
./
/
You could check if sawkForFoam offers this or program your own. For this purpose you could take a look at the parabolic inlet boundary conditions.
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boundary condition, pre-processing, u folder, velocity inlet

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