[Getdp] Symmtry problem

[gilles quemener]

Hi Jasper, 

Thanks for your answer. Indeed we agree on the symmetry ( XY or Z=0 plane) and anti-symmetry planes 
(XZ or Y=0 plane and YZ or X=0 plane). For the scalar potential approach, the antisymmetry planes 
XZ and YZ should have 0 scalar potential. I will check again, I have probably done a mistake somewhere. 
I should try to solve using vector potential as well, but I am less used to it. 

Best regards, 

Gilles 

> De: "Jasper" <funkybob at gmail.com>
> À: "Gilles Quéméner" <quemener at lpccaen.in2p3.fr>
> Cc: "getdp" <getdp at onelab.info>
> Envoyé: Samedi 16 Septembre 2017 22:12:45
> Objet: Re: [Getdp] Symmtry problem

> Hi Gilles,
> If I look at your picture, both the XZ and YZ plane should have the
> "anti-symmetry" boundary condition I think?
> XY should probably have a symmetry condition.
> I simulated a similar structure once with a vector potential formulation and
> used the following boundary conditions on 1/8 of a sphere:

> SurfAir = Region[ 300 ];
> SurfSym = Region[ 310 ];
> SurfAsym = Region[ { 320, 321 } ];

> Constraint {
> { Name a; Type Assign;
> Case {
> { Region SurfAir; Type Assign ; Value 0.; }
> { Region SurfSym ; Type Assign ; Value 0. ; } // Symmetry cuts
> }
> }
> }

> So the "anti-symmetry" does not get any constraints and due to the symmetry
> constraints it appears a gauge constraint is no longer required.
> Not sure if this translates to the scalar potential.

> Best regards,

> Jasper

> On Fri, Sep 15, 2017 at 3:45 PM, gilles quemener < [
> mailto:quemener at lpccaen.in2p3.fr | quemener at lpccaen.in2p3.fr ] > wrote:

>> Hi,

>> Currently I am trying to formulate and solve a magnetostatic problem using the
>> scalar potential method.
>> This problem is sketched on the attached picture. I have some difficulties
>> finding how to formulate the boundary
>> conditions when simulating only 1/8 of the problem.

>> For the Z = 0 plane it's fine w/ Neumann BC,i.e.t nothing in the formulation.
>> For the Y = 0 plane, I use Dirichlet BC with null scalar potential.
>> My problem is how to express the anti-symmetry : upward field / magnetization in
>> permanent magnets on X>0
>> and downward direction in the X<0 half space.
>> I have tried to require null scalar potential on plane X=0, but the answer does
>> not look correct.
>> Without any condition on this X=0 plane, I also get incorrect results.
>> Could it be only null scalar potential on the Z-axis ? Then I am a bit confused.

>> Thanks for any help,

>> Gilles



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