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defining and using varibales in velocity boundary file

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Old   April 6, 2018, 14:04
Default defining and using varibales in velocity boundary file
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Saideep
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Hi;

I am aware independently of the "partialSlip" and "groovyBC" boundaries.

For my velocity boundary, I would like to use a partialSlip condition like:
Code:
wall
{
type partialSlip;
valueFraction uniform 0.3;
}
The value fraction is given by: D/(D+2l) where D is the cell size in normal direction and l is the slip length.

However, my cell normal distance is not a constant and varies along the length of the channel. In short, I would like to use groovyBC with the following expression "mag(delta)/(mag(delta)+slip)" where delta is distance between face center on boundary to the cell center.

Unfortunately, this would not capture the tangential component then.

Is it possible to specify variables in the velocity boundary file for "slip=1" and "cellDist=mag(delta)" and use the above mentioned equation?
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Old   April 6, 2018, 15:27
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Evren Linda
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If I understood you question well, then yes you can use inline calculations (See Section 4.2.13 of the User Guide version 5.0).
Here is an example:
Say I want to calculate a variable
Code:
A = A0 * sin(omega * t)
; then

Code:
A0     2.0;  //
omega  12.0;
t      7.0;
A    #calc "$A0 * sin($omega * $t)";
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boundary condition u, partial slip, variable definition

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