[Paraview] warp by vector field(displacement) with pressure field problem

[Umut TABAK]

Dear Kenneth and Cory,

Yes, indeed, I was missing this detail. The reason what made me think wrong
is that on a 3d model I was not observing this behaviour with a similar
approach(At least, that is what I think). See the attached pictures on a 3d
post-processing view which also has a lot of zeros in the input file except
for the z-direction displacement field.

In the sliced figure for the 3d example, you can also see that the mesh
elements at the top face are deformed too much. On one side of the mesh
they are moving out of the box and on the other side they are moving into
the box(one is basically compressing the air and the other side is
expanding which is of course exaggerated too much).

I was thinking that the same approach should also hold for the 2d case. At
the end, what I would like to do is to displace the structure with the
vector field and show the pressure profile as a color field on this
deformed mesh. Since pressure is a scalar, I thought that using the scalar
pressure values at the deformed locations of the nodes would give me what I
want. But apparently for 2d case, this is not happening(for 3d case, I
still believe it is working if I look at the results).

Is not my interpretation correct?

Ps. I will send another mail excluding paraview list with the input vtk
file for one set of data to your mail addresses for a further check if you
have time.

Thanks for the help in advance.

Regards,
Umut



On 14 June 2018 at 18:22, Moreland, Kenneth <kmorel at sandia.gov> wrote:

> Umit,
>
>
>
> I took a look at your data, and the warp by vector filter is behaving
> exactly how I would expect.
>
>
>
> The displacement field in your data is 0 everywhere except at the top
> edge. Thus, when you apply the warp the top edge will move and everything
> else will stay fixed where it is. In the middle of the top edge the warp
> vectors are pushing down into the rest of the mesh. This is causing some
> self-intersection with the mesh, which is why you are seeing the pressure
> profile sticking out the top.
>
>
>
> You can use the Threshold filter to remove all cells that are not moving.
> However, that is only going to leave the top layer of cells, which I’m not
> sure what you want.
>
>
>
> -Ken
>
>
>
> *From:* ParaView [mailto:paraview-bounces at public.kitware.com] *On Behalf
> Of *Umut TABAK
> *Sent:* Wednesday, June 13, 2018 11:38 PM
> *To:* ParaView <paraview at paraview.org>
> *Subject:* [EXTERNAL] [Paraview] warp by vector field(displacement) with
> pressure field problem
>
>
>
> Dear all,
>
>
>
> On a 2d model, I am trying to plot some mode shape for a coupled
> fluid-structure problem where a beam is coupled to a cavity domain. I have
> two variables for this problem: scalar pressure variable for the cavity and
> the displacement vectors for the beam at the top edges of the domain.
>
>
>
> I am writing the attached vtk input file with my post processing codes.
>
>
>
> And the result is somewhat as expected except that another pressure
> profile with an undeformed structural part is also visible with what I
> actually want to get. Please see the attached screenshot with the settings
> and visible fields.
>
>
>
> Do I have a misunderstanding to accomplish this task. At the end, I would
> like to show the pressure profile which is a scalar field in the file along
> with the displacement field on the beam at the top edge.
>
>
>
> I was thinking if there is deformed+undeformed visibility selection
> somehwere or not, maybe the issue is completely something else.
>
>
>
> Any comments are appreciated.
>
>
>
> BR,
>
> Umut
>
>
>
> P.S. For a decent view for the deformed vector field, you can set the
> scale factor of the warpbyvector field to 0.1 to 0.15
>
>
>
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