[Getdp] Postprozessing:Curl of Curl

[Kubicek Bernhard]

Thank you very much for your reply.
My initial intention was this:
Having a current distribution, one calculates the magnetic vector potential.
Afterwards, in the post-processing, I would have liked to calculate the difference between the original current and the one obtained by rot rot A, to obtain a local error estimation, e.g. for mesh refinement.
Clearly, this was quite stupid, since a second derivative of a the linear finit element function space is mostly undefined.

Thank you very much again,
Bernhard Kubicek

-----Ursprüngliche Nachricht-----
Von: Andre Nicolet [mailto:andre.nicolet at fresnel.fr] 
Gesendet: Freitag, 11. August 2006 12:15
An: Kubicek Bernhard
Betreff: Re: [Getdp] Postprozessing:Curl of Curl


It does not make sense to compute the Curl Curl of a quantity obtained 
via the weak formulation of a second order operator. A is in the edge 
element space, Curl A is in a subspace of the face element space but a 
further derivation does not make sense in this framework. Your options are:
1) you do not really need Curl Curl A...
2) you need Curl Curl A "in a weak sense" i.e. in an integral the 
integrand of which is something like w.Curl Curl A where w is some 
(vector) weight factor so that you can integrate by part to obtain 
something like Curl w.Curl A for the integrand...
3) completely change your formulation...
Think about this!
Andre


Kubicek Bernhard a écrit :
> Hi!
> Does anyone know how to postprocess a current that is defined by a 
> formulation-calculated magnetic vector potential? I tried
> 1/mu0*{Curl {Curl A}}
> , with A being a BF_Edge, Form 1,
> but getDP complained the line in the preprocessing.
>
> Thank you, and a nice greetings,
> Bernhard
>
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Prof. André Nicolet
Université Paul Cézanne
Institut Fresnel (UMR CNRS 6133)
Domaine Universitaire de Saint-Jérôme
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E-mail: andre.nicolet at fresnel.fr 


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