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maria hofer (maria)
New member Username: maria
Post Number: 1 Registered: 11-2009
| Posted on Wednesday, November 25, 2009 - 02:53 pm: | |
Hello to the FlexPDE team, I try to model the diffusion of a substance that is constantly added in a specified region of the problem domain (e.g. the constant flow of pollutants into a lake). I'm not sure if I get the idea of doing that in FlexPDE correctly. So far I tried setting the value of the parameter "Q" (the source term) in the source region. Does this model the constant addition of the substance? Or is it a "one-time" addition of the specified value? I also tried setting a VALUE boundary condition in the region representing the source. The result seems ok; but in this case I don't have the source term "Q" in my equation anymore, which changes the given description of the problem. Any hints? Thanks a lot in advance, Maria
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Marek Nelson (mgnelson)
Moderator Username: mgnelson
Post Number: 162 Registered: 07-2007
| Posted on Friday, November 27, 2009 - 02:45 pm: | |
In the diffusion equation DIV(K*GRAD(U))+Q = DT(U), Q is a source per unit volume per unit time. A VALUE boundary condition sets the value of a variable at that boundary. If you use it, you should be sure that this correctly describes the system you want to solve.
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