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-   -   trouble with `pressureDirectedInletVelocity' (https://www.cfd-online.com/Forums/openfoam-solving/68908-trouble-pressuredirectedinletvelocity.html)

 yohey October 6, 2009 03:38

trouble with `pressureDirectedInletVelocity'

1 Attachment(s)
Hi.

I'm using OpenFOAM-1.6.x on Ubuntu 8.04 and in trouble with `pressureDirectedInletVelocity' boundary.

I'm working on the attached case. This case contains direction-fixed boundary as
inletDirection uniform (1 1 0);
But, with this condition, the velocity in the mesh next to boundary is dobuled.
This is because of `operator=' in `pressureDirectedInletVelocityFvPatchVectorField.C '.
fvPatchField<vector>::operator=(inletDir_*(inletDi r_ & pvf));
So, I modified the `inletDirection' as (1/sqrt(2) 1/sqrt(2) 0).
inletDirection uniform (0.707107 0.707107 0);
This worked correctly.

(1) Next, I tried with more precise value.
inletDirection uniform (0.70710678 0.70710678 0);
But, calculation fails with this boundary.

(2) Actually this problem is derived from `pressureDirectedInletVelocityFvPatchVectorField.C '. So, I modified such sentence in this file as
fvPatchField<vector>::operator=(inletDir_*(inletDi r_ & pvf)/magSqr(inletDir_));
This modification also crashes calculation.

I can't understand these behavior of (1) and (2).

Would anyone help me to find the cause of these problems?

Sincerely.

Yohey

 aliqasemi August 10, 2011 11:42

Yohey[/QUOTE]
Quote:
 Originally Posted by yohey (Post 231587) Hi. (1) Next, I tried with more precise value.inletDirection uniform (0.70710678 0.70710678 0); But, calculation fails with this boundary. Yohey
This is because some of the faces in the patch are normal to the vector you specified for inletDirection, which causes a division by zero in the file pressureDirectedInletOutletVelocityFvPatchVectorFi eld.C. Changing the code or the value for inletDirection should fix the problem. I had the same problem using using OF.1.7.1, nearly two years later.

 akashjangid October 4, 2013 11:15

Inlet Angle

Hello

I am doing simulation on a rotor blade.
Does anyone know how to give the inlet angle like this (which depends on z and y)
dir_cos1 = 4.04
dir_cos2 = EXPR{57.2958*(acos(0.07045*(z/sqrt(z*z+y*y))))}
dir_cos3 = EXPR{57.2958*(acos(-0.07045*(y/sqrt(z*z+y*y))))}

Thanks !!

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