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Subject: Re: [EMAG] [POST] display of magnetic flux lines for 3D
Author: Dave Lindeman
Date: 2008-04-14 15:11:43

Peter:

From the documentation for *VPUT:

"Degree of freedom results that are replaced in the database are
available for all subsequent postprocessing operations. Other results
are changed temporarily and are available mainly for the immediately
following print and display operations."

So, the EF components you *VPUT will only be there temporarily. Plus
you'd have to determine what charge and mass to define for the particles
to keep them from wandering away from the streamlines.

I don't have a FLOTRAN template that I can share, but you have the
general idea. Use FLDATA to define the most basic CFD analysis you can
(e.g., stick with the defaults and use one of the pre-defined material
property sets). Since you will be completely defining the velocity
field and only performing one iteration, it should be pretty easy to get
things to run.

Regards,

Dave

-------------------------
Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383


Peter Frei wrote:
> Dave,
>
> Thanks for the hint regarding Flotran. I agree about PLTRAC being not as
> general purpose as it could be.
>
> Your post inspired me to try another workaround that does not involve
> Flotran. I thought that it might be possible to use the electric field
> tracing option of PLTRAC since there's no cross product in the electric
> field part of equation (5-258):
>
>> m {a} = {F} = q ( {E} + {v} x {B} ). (5-258)
>
> So it tried *VGETting the B field data into an array and *VPUTting it
> subsequently into to electric field EF results data. That seemed to work,
> at least PRNSOL,EF showed the correct values. Unfortunately, neither
> plotting the EF data itself nor plotting the particle trace worked. When
> trying to plot the electric field data, all EF values seem to be zero.
> PLTRAC generates an error ("No field data for element #"). The code I used
> is attached below.
>
> In case you still have an APDL script somewhere that transfers the B field
> data to Flotran, I'd be interesting at having a glance at it. I guess it
> would roughly consist of the following steps:
> 1. *VGET the B field data into temporary array
> 2. Change all element types to FLUID142
> 3. Apply the B field as velocity boundary condition (D command, VX, VY, VZ
> dofs)
> 4. Solve
> 5. Postprocess (PLTRAC)
> Unfortunately, I'm not familiar with Flotran so I'd first have to go
> through the sample Flotran analyses in the Ansys manuals.
>
> Kind regards,
>
> Peter
>
>
> !!Retrieve results of emag analysis:
> RESUME, [your_db_name_here], db
> !!(e. g. results from SOLID117 edge-based analysis)
>
> /POST1
> ALLSEL
>
> !!Determine the number of nodes in the model:
> *GET, anznode, NODE, 0, NUM, MAX
>
> !!Create arrays for the temporary storage of B data:
> *DEL, tempbx, , NOPR
> *DEL, tempby, , NOPR
> *DEL, tempbz, , NOPR
> *DEL, tempbsum, , NOPR
> *DIM, tempbx, ARRAY, anznode
> *DIM, tempby, ARRAY, anznode
> *DIM, tempbz, ARRAY, anznode
> *DIM, tempbsum, ARRAY, anznode
>
> !!Fill the temporary storage with the B data:
> *VGET, tempbx, NODE, , B, X
> *VGET, tempby, NODE, , B, Y
> *VGET, tempbz, NODE, , B, Z
> *VGET, tempbsum, NODE, , B, SUM
>
> !!Check contents of the temporary storage:
> *STATUS, tempbx
> *STATUS, tempby
> *STATUS, tempbz
> *STATUS, tempbsum
>
> !!Add VOLT degree of freedom (not sure if this is needed):
> DOF, VOLT
>
> !!Fill the electric field data with the contents of the temp.
> storage:
> *VPUT, tempbx, NODE, , EF, X
> *VPUT, tempby, NODE, , EF, Y
> *VPUT, tempbz, NODE, , EF, Z
> *VPUT, tempbsum, NODE, , EF, SUM
>
> !!Print the contents of the electric field data:
> PRNSOL, EF
>
> !!Check some plots:
> /TYPE, ALL, BASIC !!show interior arrows also
> PLVECT, B, , , , VECT, ELEM, ON, 0 !!B field vector plot; works ok
> PLVECT, EF, , , , VECT, ELEM, ON, 0 !!E field vector plot; does
> not work
>
> !!Particle trace test:
> TRPDEL, ALL !!delete existing trace points (if any)
> TRPOIN, -10E-3, 0, 0, 0, 0, 0, -1.6e-19, 9.1e-31 !!particle =
> electron
> PLTRAC,ELEC, , ,0,TRAC,1000,1e-008, ,1,1
>
> _________________________________
> Dr. Peter U. Frei
> Rockwell Automation AG
> IEC Power Components, Dept. ER
> Buchserstrasse 35
> CH-5001 Aarau
> Switzerland
> pfrei_at_ra.rockwell.com
> Phone: +41 62 837 24 47
> Fax: +41 62 837 29 17
>
>
>
> Dave Lindeman
> Sent by: xansys-bounces_at_xansys.org
> 10.04.2008 19:24
> Please respond to
> ANSYS User Discussion List
>
>
> To
> ANSYS User Discussion List
> cc
>
> Subject
> Re: [Xansys] [EMAG] [POST] display of magnetic flux lines for 3D
> analysis
>
>
>
>
>
>
> No, there is no easy way to plot flux lines (or even pseudo-flux lines)
> for a three-dimensional model in ANSYS. The only work-around I've found
> is to setup and run a dummy FLOTRAN analysis using the nodal B-field
> components to define the nodal velocity components as boundary
> conditions. This isn't too painful since you can script it all using
> APDL and the FLOTRAN analysis requires only one iteration. Following
> solution you can use PLTRAC to create the pseudo-flux lines (i.e., lines
> parallel to the B field).
>
> Clearly ANSYS has streamline plotting capabilities. Why they treat some
> vector fields as less worthy than others, I don't know. EnSight and
> other general-purpose postprocessors don't enforce any such
> restricitions -- you can plot streamlines through your displacement
> field if you really want to. I'd prefer the code let ME make the choice
> and let ME be responsible for interpreting the results rather than
> arbitrarily restricting what can be done with a given tool. People have
> been asking for support of electromagnetic vector fields in PLTRAC for
> at least a decade now. If ANSYS has implemented their streamline
> algorithm in anything resembling a general-purpose fashion, then I'd
> have to imagine this "enhancement" could be added in ten minutes or
> less. But that would be ten minutes less they could spend on Workbench...
>
> Dave
>
> -------------------------
> Dave Lindeman
> Lead Research Specialist
> 3M Company
> 3M Center 235-3F-08
> St. Paul, MN 55144
> 651-733-6383
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Posts possibly associated with message #92846AuthorDateScore
92791Re: [EMAG] [POST] display of magnetic flux lines for 3DDave Lindeman2008/04/10 
92811Re: [EMAG] [POST] display of magnetic flux lines for 3DPeter Frei2008/04/11 
92815Re: [EMAG] [POST] display of magnetic flux lines for 3DPeter Frei2008/04/11 
92846Re: [EMAG] [POST] display of magnetic flux lines for 3DDave Lindeman2008/04/14