# velocity U in the Calculator- Problem

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 March 21, 2014, 20:10 velocity U in the Calculator- Problem #1 Member   ziehjay Join Date: Jul 2013 Posts: 43 Rep Power: 4 Hey guys, i am working with the tool calculator in paraview right now. Unfortunately it does not accept my U as a scalar value, when i want to integrate the velocity U in my calculation. This error occurs: ERROR: In /home/sanjar/OpenFOAM/ThirdParty-2.2.x/ParaView-3.12.0/VTK/Charts/vtkPlotPoints.cxx, line 641 vtkPlotLine (0xdc0b280): No Y column is set (index 1). Does somebody has an answer or a suggestion how to fix this problem? Background of this problem: Bridge ANSYS and paraview thank you guys and thanks for every helping suggestion!!

 March 24, 2014, 13:49 #2 Member   ziehjay Join Date: Jul 2013 Posts: 43 Rep Power: 4 hey guys, anybody out there who could say what the problem might be..? still couldnt figure it out :/ thanks!

March 25, 2014, 09:26
#3
Member

ziehjay
Join Date: Jul 2013
Posts: 43
Rep Power: 4
hey guys,
i thought it would make sense if i explain and show you the things i did so far to solve my problem.

AIM: get the same plots like the ones from ANSYS (see pic 1)

1. typed into calculator the formular p + (0.5*997.561*(UČ))
- 997.561 is the density of water
- U is my veloocity, but it did not work because calculator did not accept the scalar, so i just typed in my starting velocity at the inlet 13 m/s
--> Result: got a plot like in pic 2,3,4

--> Problem: all three plots do not start from 0 respectivey from a negative point like in ANSYS, because i used 13, 9 and 5,4 m/s and not the scalar

2. tried to check if a got velocity on my plate of my geometry, there is no velocity

--> looking: Bridge ANSYS and paraview

changed my BCs from --> to

Code:
```dimensions      [0 1 -1 0 0 0 0];

internalField   uniform (0 -5.4 0);
boundaryField
{
WALL
{
type            fixedValue;
value           uniform (0 0 0); --> (0 -5.4 0)
}
OUTLET
{
type            pressureInletOutletVelocity;
value        uniform (0 0 0);
}
EROSIONPLATE
{
type            fixedValue;
value           uniform (0 0 0); --> (0 -5.4 0)
}
INLET
{
type            fixedValue;
value           uniform (0 0 0); --> (0 -5.4 0)
}```
now i got the velocity on my plate which is constantly 5,4; 9 and 13 m/s
but i generate such plots if i use calculator and the vector U_Y or even the normal velocity of 5.4 m/s (see pic 5)

I really dont know where my problem is?

if there is somebody who could help me, please spend some minutes and explain/show it to me..its pretty important!

thanks!
Attached Images
 vergleich_2.jpg (72.6 KB, 2 views) Vergleich_13.0.jpg (47.5 KB, 1 views) Vergleich_9.1.jpg (50.0 KB, 1 views) Vergleich_5.4.jpg (42.0 KB, 1 views) Bildschirmfoto vom 2014-03-25 14:24:24.jpg (47.5 KB, 1 views)

 March 25, 2014, 14:38 #4 Senior Member   Joachim Herb Join Date: Sep 2010 Posts: 291 Rep Power: 9 Do you plot the velocity on a wall? Then it is set by the boundary conditions to be 0. So the result is correct. Are your boundary conditions the same in ANSYS and OpenFOAM? It looks like you might be using free slip conditions in ANSYS and no slip in OpenFOAM for that wall? Can you post your 0/U file of OpenFOAM and (parts of) the ccl file of Ansys (if you use CFX)?

March 25, 2014, 14:47
#5
Member

ziehjay
Join Date: Jul 2013
Posts: 43
Rep Power: 4
hello,

no i plo the velocity on the plate, where the flow is sprinkling on. (i uploaded a pic which i made in paint a long time ago :-) )
above your post there is my 0/U file.
i dont think that it has something to do with the BCs in OF and in ANSYS because my plot in OF has the same peak (maximum) like the one in ANSYS.

the problem for me is the y- axis (y-achsenschnittstelle) because it does not start with 0 but with a higher value. and this value comes from the formule i use in the calculator, which you can see above.

i tried to plot just the normal pressure (relativdruck, also ohne diese formel) and this one was right because it also starts from negative y-axis but i dont reach the peaks.

so all in all, it has smething to do with the problem that i cant use my scalar AND vector U in the calculator. Both doesnt work.

thank you for your attention.
Attached Images
 SA.jpg (48.9 KB, 2 views)

 March 25, 2014, 17:10 #6 Member   ziehjay Join Date: Jul 2013 Posts: 43 Rep Power: 4 nevertheless joachim, i am still looking forward for new suggestions!

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