[Getdp] problem solution permanent magnets-getdp

Jasper funkybob at gmail.com
Mon Feb 25 18:33:41 CET 2013


Hello Frederic,

I did not try your new files, but for me your initial problem got
solved correctly by issuing a "Coherence;" (not "Coherence Mesh;"!)
command after "Plane Surface(6) = {7, 6};" in your .geo file.

I think Gmsh hat gotten better over the years at detecting duplicate
geometric features, but still I always try to define them uniquely to
prevent these kinds of problems.

Best regards,

Jasper

On Mon, Feb 25, 2013 at 5:30 PM, Frederic Trillaud
<ftrillaudp at pumas.ii.unam.mx> wrote:
> Hi,
>
> I did a couple of tests with different ways to create the same geometry
> for a permanent magnet problem. It appears that you have to create the
> geometry in the following manner to get a proper result:
>
> 1- Create all the points of the geometry only once, do not duplicate
> points for geometries sharing same boundaries
> 2- use previously created lines and arcs for geometries sharing the same
> lines and arcs (same idea as for the points)
>
> Duplicating points and lines/arcs etc..., even though using "Coherence"
> function triggers some undesirable effects on the solutions (see
> attached files).
>
> Best,
>
> Frederic
>
> On Sun, 2013-02-24 at 19:08 +0100, Jasper wrote:
>> Hi Frederic,
>>
>> The issue is with your geometry definition. Shared edges of surfaces
>> use multiple lines and circles. As such you have to issue a
>> "Coherence" command before defining your physical groups.
>> A beter way forward would be to make sure lines and circles are
>> uniquely defined (i.e. only once).
>>
>> Best regards,
>>
>> Jasper
>>
>> On Sat, Feb 23, 2013 at 9:52 PM, Frederic Trillaud
>> <ftrillaudp at pumas.ii.unam.mx> wrote:
>> > Hi,
>> >
>> > I have been doing some tests on permanent magnets. I am having some
>> > issues with the magnetic solution of a problem involving 2 permanent
>> > magnets. The solution of the magnetic field looks awkward.
>> >
>> > Here are the files and a pic of the geometry showing the magnets. If
>> > someone has an opinion on what may be the reason of the obtained flux
>> > lines.
>> >
>> > To run the example, I have created the script main.sh which generates
>> > the mesh, solve and generate the pos files.
>> >
>> > Best,
>> >
>> > Frederic
>> >
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>> >