Get scalars of scaled coordinates

[homerun4711]

Hello,

I have a question and hope that you can help me.

I am trying to calculate the heating of a steel part and export the temperatures at specific nodes/coordinates.

The STP-file is opened in ElmerGUI and displayed correctly. Since the geometry is exported from our
CAD software in the wrong units (scaled by 2.54, no idea why) I have to convert the units back
to meters by dividing by 0.39.

This is done by using

Coordinate Scaling = Real 0.39

This values are applied only while solving the sif-file, right?
As Model - Summary shows still the enlarged bounding box...

So I guess the result of the calculation has the correct units then.

I would like to read the temperatures at specific coordinates using SaveScalar.
Do I have to enter the "wrong" or the "right" coordinates here:

Save Coordinates(n,DIM) Real
Exact Coordinates True

Kind regards,
Markus

[mzenker]

Hi,

I think you have to enter the "right" coordinates, i.e. after Coordinate Scaling has been applied.

Matthias

[homerun4711]

I am trying this right now. Let's see what happens.

Do you now a way to verify this? E.g.by clicking a mesh node in postprocessing
and display its coordinates?
So far I could not find a way to do this in ElmerPost or the VTK postprocessing.

[mzenker]

Hi,

in ParaView, you can use the calculator and introduce a variable to which you assign "coords". If you then select a node, you can see its coordinates by setting Point Label to Visible and Label Mode to your new variable in the Selection Inspector.

HTH,

Matthias

[raback]

Hi Markus

In ElmerPost you can see the range by choosing Nodes_x (and y,z) in Color Mesh and looking at the Min and Max values.

SaveScalars can also save min/max of "Coordinate i", i=1,2,3.

The scaling is done directly after reading in the mesh, and the original mesh is not maintained, so it is difficult to make a mistake if the scaling was succesfull.

-Peter

[homerun4711]

Hello,
thanks for your responses.
I used ParaView and the coordinate axes, if activated show the correct dimension, so I did not
go into detail by checking the nodes.

The scaling is done directly after reading in the mesh, and the original mesh is not maintained, so it is difficult to make a mistake if the scaling was succesfull.

Peter, does that mean, that the mesh is loaded from the four mesh.* files and converted to a temporary mesh used for the calculation?
Or does this modify the mesh.* files?

I came across another thing, but I am not sure if this a bug or a feature
Since I do not want to start a fresh thread I hope you can help me sort out
where this belongs to.

A calculation using only the following BC without an External Temperature
given executes the calculation with the External Temperature set
automatically. I guess it is set to zero, as my steel part cooled down
quickly...

Code: Select all

Boundary Condition 1
  Target Boundaries(1) = 1
  Name = "Convection"
  Heat Flux BC = True
  Heat Transfer Coefficient = 15
End

If instead only a radiation BC is set without External Temperature
or Radiation External Temperature set like

Code: Select all

Boundary Condition 1  
  Target Boundaries(1) = 1
  Name = "Radiation"
  Heat Flux BC = True
  Radiation = Idealized
  Emissivity = 0.8
End

results in the error message

Code: Select all

WARNING:: ListFind:  Requested property: [External Temperature], not found

displayed over and over the console window.

I encountered this because I accidently missed the External Temperature
and wondered why the part cooled down. In this case it was easy as I
expected it to warm up.
But I think this error should be thrown always if the
External Temperature is missing to avoid errors.
In coupled problems with overlaying effects this might not be so obvious to spot.

Kind regards,
Markus