[Paraview] Questions regarding: volume calculation, xyplot along a curve and tensor calculation

[Jie Xu]

Hi there,

I am using linux version of paraview to read .vtk data files. (Anyone
knows if I can attach documents in this mail list?) I have two
questions:

1) Volume calculation:
I found that the "integrate variables" over a sphere clip never gives
the correct volume. For example, I tried to use a very simple geometry
and a very fine mesh (a 200x200x200 micron cube with 2 micron cube
elements), and use paraview to generate a sphere clip that has radius
of 50 micron in the center of that cube, then I apply the "integrate
variables" filter to the clip and show the "Cell Data", it gives a
volume of 4.78818e-13 instead of 5.236e-13, which is 4/3*pi*r^3. The
discrepancy is so large that it just cannot be due to the coarseness
of the mesh. Different mesh and different size of clips gives
different discrepancies, and I cannot find any obvious relationship
between the paraview-calculated volume and the real volume.

2) X-Y plot: how can I do a xyplot of a scalar along a curved line?
For example, if I have the pressure field data from a
flow-around-a-cylinder case, I want to plot the pressure along the
surface of the cylinder as a function of angle or arc length.

3) tensor calculation: I have the pressure field and velocity field
calculated from a CFD tool (Transat in my case), how do I calculate
stress tensors at each point from P V field in paraview?

I am new to paraview and this mail list, please let me know if I asked
any inappropriate questions. Thanks in advance for your kind help.

Regards,
Jie