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Parametric Sweep in order to change the location of a point

Posted 18 mars 2013, 10:46 UTC−4 Modeling Tools & Definitions, Parameters, Variables, & Functions, Studies & Solvers Version 4.3 3 Replies

Rama Sandovsky
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Hi,

I'm using the Parametric Sweep in order to change the location of a point who separate edge into two lengths; each has a different boundary condition. (One defined by me and the other one is the default condition -zero flux)
The location of the point (defined by the parameter "d2" in the y-axis and on the edge at the x-axis) defines the distance which is the size controlled by the B.C defined by me.
The problem is, whenever the parameter "d2" been modified, the B.C (who defined by me) go through all of the edge regardless to the point location.
Thank you in advance
3 Replies Last Post 22 mars 2013, 09:33 UTC−4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 18 mars 2013, 14:14 UTC−4
Hi

try useing a Definition - Selection node where you define each bondary and then refer to that Selection rather to the individual items.

Also it would perhaps (just a guess) work better if you define the line a s a polylineof 2 segments and not just an added "point". It probably has to do with the element id numbering algorithm, you point is displacing such that COMSOL identifies a topology change, and then it get lost in the element renumbering. The selection often (but not alwys) helps.

--
Good luck
Ivar
Hi try useing a Definition - Selection node where you define each bondary and then refer to that Selection rather to the individual items. Also it would perhaps (just a guess) work better if you define the line a s a polylineof 2 segments and not just an added "point". It probably has to do with the element id numbering algorithm, you point is displacing such that COMSOL identifies a topology change, and then it get lost in the element renumbering. The selection often (but not alwys) helps. -- Good luck Ivar
Rama Sandovsky
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Posted: 1 decade ago 22 mars 2013, 04:14 UTC−4
Hi Ivar,
Thanks for your quick answer.
I tried all of your recommendation to fix the problem but unfortunately nothing worked.
My problem is a bit complicated so I tried to do the same Parameter Sweep with a really simple heat transfer problem; include rectangle that one of its edges has temperature B.C and convective cooling B.C on part of other edge, all the other boundaries have the default condition.
Again, when I changed the size of the parameter that controlled the lengths of the B.C one of the condition expend all over the edge. One thing I notice, it take the B.C of the boundary numbered 1(the other part of the edge numbered 3) no matter what B.C defined for both part.
I tried to play in this simple problem with a different parameter but nothing solves the problem.
Do you have any other suggestion to fix this problem?
Thank you again,
Rama

Hi Ivar, Thanks for your quick answer. I tried all of your recommendation to fix the problem but unfortunately nothing worked. My problem is a bit complicated so I tried to do the same Parameter Sweep with a really simple heat transfer problem; include rectangle that one of its edges has temperature B.C and convective cooling B.C on part of other edge, all the other boundaries have the default condition. Again, when I changed the size of the parameter that controlled the lengths of the B.C one of the condition expend all over the edge. One thing I notice, it take the B.C of the boundary numbered 1(the other part of the edge numbered 3) no matter what B.C defined for both part. I tried to play in this simple problem with a different parameter but nothing solves the problem. Do you have any other suggestion to fix this problem? Thank you again, Rama
Juergen Hansmann
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Posted: 1 decade ago 22 mars 2013, 09:33 UTC−4
Hi Rama,

please have a look at the attached model. It does not have any physical meaning and the values of properties are randomaly chosen. It is just meant to serve as a quick demonstration.

In this model positions of one point on the left and one point on the right boundary are changed by a parametric sweep (the parameter is "y_pos").
The selections of the boundary conditions "Atmosphere/Gauge 1" and "Hydraulic Head 1" are done using the selections "Box 1" and "Box 2" (Model 1 node -> Definitions, as Ivar suggested), which both depend on the "y_pos" parameter.

In this example model it works.
Maybe you can use a similar approach for your model?

Best regards,
Juergen

Hi Rama, please have a look at the attached model. It does not have any physical meaning and the values of properties are randomaly chosen. It is just meant to serve as a quick demonstration. In this model positions of one point on the left and one point on the right boundary are changed by a parametric sweep (the parameter is "y_pos"). The selections of the boundary conditions "Atmosphere/Gauge 1" and "Hydraulic Head 1" are done using the selections "Box 1" and "Box 2" (Model 1 node -> Definitions, as Ivar suggested), which both depend on the "y_pos" parameter. In this example model it works. Maybe you can use a similar approach for your model? Best regards, Juergen

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