Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

operateur "dest" libre

Please login with a confirmed email address before reporting spam

Bonjour à tous,

J'ai quelques problèmes avec l'opérateur "dest" de COMSOL.

Je souhaite calculer l'intégrale de y sur une surface.
J'entre donc dans Boundary/ integration coupling variable

Name : toto
Expression : dest(y) (puisque ma variable d'intégration est y)
Destination globale

A priori cette expression ne dépend pas de "y"puis "y" est ma variable d'intégration.

Pourtant après avoir calculé cette intégrale et en utilisant l'option postprocessing / Plots parameters / Slice COMSOL montre que la solution dépend de étrangement de "y" puisque des slices crées en différentes positions (y = 1, y = 2...) me donnent des cartes différentes comme si la solution dépendait de la position du slice suivant "y" c'est-à-dire de "y" ce qui n'est pas attendu.

Quelqu'un peut -t-il donc m'expliquer simplement à quoi sert l'opérateur "dest" et comment on l'utilise. D'après ce que je comprends dest(y) signifie que la variable d'intégration est "y". Est-ce juste ? Et donc que par exemple (x-dest(x)) entrée dans integration coupling variable correspond à l'integrale [(x-x') dx'dy'dz'] où dest(x) = x'.

La page 165 du "user's guide" ainsi que la page 129 du "modele library" ne parlent que très peu de cet opérateur et les exemples ne sont pas très riches. Les différents documents proposés par COMSOL semblent considérer que cet opérateur est une évidence.
Il semblerait aussi que je l'utilise très mal !

Je vous serai très reconnaissant de m'aider dans ma quête !

Cordialement

Pierre



1 Reply Last Post 21 giu 2010, 12:58 GMT-4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 21 giu 2010, 12:58 GMT-4
Hi

it is true that the dest() operator is not that much explained, I use it in the coupling variables, particularly to get the values exrteacted from the destination, when I define a source and a destination for my variables (2nd and 3rd tab), because when you say "x" from where is it taken, if destination = source it's easy, but if you define the destination <> the source you have two "x"'s, dest(x) then explicitely apply to the destination, as defined in the coupling integration operator.

One way is to get the length (or area or volume) of a certain number of items, then writoing "(dom==dest(dom))" gives you a bolean operator = 1 if source = destination and 0 otherwise, this defines the Length respectively Area or volume of EACH selected item, and not the total length of all.

Hope this helps
And by the way try to stick to english, that helps for the non-French-speaking community

Bonne soirée
Ivar
Hi it is true that the dest() operator is not that much explained, I use it in the coupling variables, particularly to get the values exrteacted from the destination, when I define a source and a destination for my variables (2nd and 3rd tab), because when you say "x" from where is it taken, if destination = source it's easy, but if you define the destination the source you have two "x"'s, dest(x) then explicitely apply to the destination, as defined in the coupling integration operator. One way is to get the length (or area or volume) of a certain number of items, then writoing "(dom==dest(dom))" gives you a bolean operator = 1 if source = destination and 0 otherwise, this defines the Length respectively Area or volume of EACH selected item, and not the total length of all. Hope this helps And by the way try to stick to english, that helps for the non-French-speaking community Bonne soirée Ivar

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.