[Getdp] 2D axisym. coil

David Colignon david.colignon at ulg.ac.be
Mon Aug 10 18:55:08 CEST 2015


On 10/08/15 17:14, Frederic Trillaud Pighi wrote:

> Dear Peter,
>
> It reminds me of the integral constraint in COMSOL. I do not know in GetDP. As far as I know, you
> can provide constant values for the constraint but I am not sure how you can use out of the box a
> function to implement the integral constraint. It may require some extra-implementation. The other
> option is to solve it as an extra equation: Int (Jext+sigma*E-J) = 0 where J is an homogeneous
> current density J = I/Omega_coil. Not sure if it makes sense for your problem.
>
> Hopefully, someone has an appropriate answer to your problem. I would be interested to know how it
> could be implemented. I may need it down the road.


Hi,

maybe should you have a look at "global quantities" in the manual ?

Regards,

Dave

-- 
David Colignon, Ph.D.
1er logisticien de recherche
Université de Liège
ACE - Applied & Computational Electromagnetics
Sart-Tilman B28
10, Grande Traverse
4000 Liège - BELGIQUE
Tél: +32 (0)4 366 37 32
http://www.ulg.ac.be/nic4
>
> Best,
>
> Frederic
>
>
>
>> On Aug 9, 2015, at 4:28 PM, Peter Kis <md2z34 at gmail.com <mailto:md2z34 at gmail.com>> wrote:
>>
>> Dear Frederic,
>>
>> a big thank to you for helping me out of this. The model with your modifications works like a
>> charm. I am amazed how could you figured out the problem with the initial conditions. How could
>> you catch this?
>>
>> I compared the results given by getdp with COMSOL and it's a perfect match! I am very pleased.
>>
>> I continue developing this model. Because I still need to add a special constraint which should
>> enforce not the external current density to the coil but the net current. That is int_Omega_coil
>> (Jext + sigma*E) = I, where E is the electric field E= -dA/dt. It's a kind of iteration thing
>> because the total net current depends on the result (A). Do you think such constraint is possible
>> in getDP?
>>
>> Thanks again,
>>
>> Kind Regards
>>
>>
>> Peter
>>
>>
>> On Sun, Aug 9, 2015 at 1:52 AM, Frederic Trillaud Pighi <ftrillaudp at pumas.iingen.unam.mx
>> <mailto:ftrillaudp at pumas.iingen.unam.mx>> wrote:
>>
>>     Dear Peter,
>>
>>     Here it goes. I made some changes (transformation with an outer shell,
>>     killed the initial time value of A, you should not need it) and did some
>>     tests so the parameters of current density etc. have been changed. It
>>     should work fine now.
>>
>>     Best,
>>
>>     Frederic
>>
>>
>>     On Sun, 2015-08-09 at 00:27 +0200, Peter Kis wrote:
>>     > I am sending the model files. Thanks for your time.
>>     >
>>     >
>>     > Peter
>>     >
>>     >
>>     > On Sat, Aug 8, 2015 at 11:02 PM, Frederic Trillaud
>>     > <ftrillaudp at pumas.ii.unam.mx <mailto:ftrillaudp at pumas.ii.unam.mx>> wrote:
>>     >         Send me back your files, I will take a look at it over the
>>     >         weekend to
>>     >         see if I can pin the problem.
>>     >
>>     >         Frederic
>>     >
>>     >
>>     >         -----Original Message-----
>>     >         From: Peter Kis <md2z34 at gmail.com <mailto:md2z34 at gmail.com>>
>>     >         To: Frederic Trillaud <ftrillaudp at pumas.ii.unam.mx <mailto:ftrillaudp at pumas.ii.unam.mx>>
>>     >         Cc: getdp at geuz.org <mailto:getdp at geuz.org>
>>     >         Subject: Re: [Getdp] 2D axisym. coil
>>     >         Date: Sat, 8 Aug 2015 22:43:11 +0200
>>     >
>>     >         Dear Frederic,
>>     >
>>     >
>>     >         thanks for your reply. There must be something else here,
>>     >         because
>>     >         VolAxiSqu hasn't helped.
>>     >
>>     >
>>     >         I think the time function in my code might be okay, because it
>>     >         seems to
>>     >         work fine for Jacobi Vol.
>>     >
>>     >
>>     >         Cheers,
>>     >
>>     >
>>     >         Peter
>>     >
>>     >
>>     >         On Sat, Aug 8, 2015 at 5:51 PM, Frederic Trillaud
>>     >         <ftrillaudp at pumas.ii.unam.mx <mailto:ftrillaudp at pumas.ii.unam.mx>> wrote:
>>     >                 Dear Peter,
>>     >
>>     >                 I had a similar problem, you should try VolAxiSqu. It
>>     >         solves my
>>     >                 issue on
>>     >                 the axis of symmetry.
>>     >
>>     >                 Jacobian
>>     >                 {
>>     >                  {// Dimension ND regions in plane
>>     >                   Name AxiJacobian;
>>     >                   Case
>>     >                   {
>>     >                    {
>>     >                     Region infiniteBoundaryRegion;
>>     >                     Jacobian
>>     >         VolAxiSquSphShell{0.95*infiniteBoundaryInnerRadius,
>>     >                 1.05*infiniteBoundaryOuterRadius};
>>     >                    }
>>     >                    {
>>     >                     Region All;
>>     >                     Jacobian VolAxiSqu;
>>     >                    }
>>     >                   }
>>     >                  }
>>     >                 }
>>     >
>>     >                 To apply the current density, you need to use time
>>     >         function that
>>     >                 will be
>>     >                 multiply to your current density. You have to
>>     >         implement it in
>>     >                 the
>>     >                 Constraint.
>>     >
>>     >                 Constraint
>>     >                 {
>>     >                 {
>>     >                   Name currentDensityCondition;
>>     >                   Case
>>     >                   {
>>     >                    {
>>     >                     Region inductorRegion;
>>     >                     Value currentDensity[];
>>     >                     TimeFunction timeFunction[];
>>     >                    }
>>     >                   }
>>     >                  }
>>     >                 }
>>     >
>>     >                 I use the conditional operators to create the time
>>     >         function:
>>     >
>>     >                 "timeFunction[] = If condition Then statement Else
>>     >         statement;"
>>     >                 is then
>>     >                 in conditional operators:
>>     >                 timeFunction[] = (condition) ? statement : statement;
>>     >
>>     >
>>     > http://www.c4learn.com/c-programming/c-conditional-operators/
>>     >
>>     >                 Good luck,
>>     >
>>     >                 Frederic
>>     >
>>     >                 -----Original Message-----
>>     >                 From: Peter Kis <md2z34 at gmail.com <mailto:md2z34 at gmail.com>>
>>     >                 To: getdp at geuz.org <mailto:getdp at geuz.org>
>>     >                 Subject: [Getdp] 2D axisym. coil
>>     >                 Date: Sat, 8 Aug 2015 16:57:49 +0200
>>     >
>>     >                 Dear getDP list members,
>>     >
>>     >
>>     >                 I am still struggling with my first model in getDP,
>>     >         which would
>>     >                 be a
>>     >                 single turn coil on 2D axisymmetric plane.
>>     >
>>     >
>>     >                 Now, at least I get something, but I don't like what I
>>     >         get. I am
>>     >                 not
>>     >                 sure how to apply the time dependent excitation
>>     >         current density
>>     >                 to the
>>     >                 coil. Therefore I took something over from CoreMassive
>>     >         model
>>     >                 (found on
>>     >                 the Internet).
>>     >
>>     >
>>     >                 As you can see in the attached pictures the magnetic
>>     >         vector
>>     >                 potential
>>     >                 for the pure 2D model (with Jac Vol) looks good but
>>     >         for the
>>     >                 axisym model
>>     >                 (with Jac VolAxi) it looks terrible.
>>     >
>>     >
>>     >                 Definitely there is still something here what I miss.
>>     >
>>     >
>>     >                 Any comment is highly appreciated.
>>     >
>>     >
>>     >                 Thanks in advance,
>>     >
>>     >
>>     >                 Peter
>>     >
>>     >
>>     >                 _______________________________________________
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