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Nieves Felipe (nieves)
New member
Username: nieves

Post Number: 1
Registered: 12-2008
Posted on Saturday, December 13, 2008 - 08:35 pm:   

G'day,

I'm using the student version of Flex. I'm trying to define a boundary, with both a NATURAL and a VALUE condition. The program appears to ignore the first of these, giving me different solutions depending on the order of writing. Is there any way to overcome this?

Thanks!
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Marek Nelson (mgnelson)
Moderator
Username: mgnelson

Post Number: 101
Registered: 07-2007
Posted on Saturday, December 13, 2008 - 11:06 pm:   

You can only apply one boundary condition for each variable on any boundary path. That is why FlexPDE is taking the last stated condition and ignoring the first.

The one exception is in 3D if you want to apply different BCs on different layers. You can do this by specifying the two BCs with a LAYER qualifier.
i.e.
START(0,0)
LAYER 1 VALUE(u)=1
LAYER 2 NATURAL(u)=0
...
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Nieves Felipe (nieves)
New member
Username: nieves

Post Number: 2
Registered: 12-2008
Posted on Sunday, December 14, 2008 - 05:01 am:   

I was afraid of that :/
Thank you very much Marek! :-)
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Olexiy Orel (scorpion)
Member
Username: scorpion

Post Number: 13
Registered: 03-2007
Posted on Monday, April 13, 2009 - 11:41 am:   

You can use constraints. Like I did. First BC as BC, second - as a constraint.

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