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weak form
Posted 15 nov. 2019, 05:12 UTC−5 2 Replies
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whether the dweak form in comsol has been canceled, only the weak form can be set
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What is the dweak form?
-------------------ZHANG, Pu
School of Physics,
Huazhong University of Science and Technology
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Hello,
You are right, the "dweak" term was in the past used for entering the time derivative of the unknown for time-dependent problem (there is no mathematical "dweak form", only a "weak form").
The time derivative expression can actually be entered in the "weak" term : COMSOL will detect the time derivative automatically.
So for instance a time-dependent Poisson equation with source = 1 on a 1D segment along direction x reads :
weak = ux * test(ux) - 1 * test(u) - d(u,t) * test(u)
d(u,t) is the time derivative.
you need to add boundary conditions of course.
"weak" means : integration over the selected domain (or the boundary, depending where you write the equation).
The order of the terms does not matter.
So whatever was written in the "dweak" term in old versions, you can enter it in the "weak" term without any problem.
You can find more advanced details in the documentation.
Eric Favre COMSOL France
-------------------Eric Favre
COMSOL France