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Boundary conditions (PDE general form) + high order PDE

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Hello,

I would like to solve in 1D a non-linear differential equation of order 2. I use a PDE general form with the following settings (one variable c):
Gamma = -3*(1+theta*c)*cx
F = theta*cx^2-3*theta*cx
ea = 0
da = 1
Is it possible to put F equal to high order derivatives (for example to put F=cxxxx)?
Moreover I have the following boundary conditions:
Gamma must be constant at the boundary 2: for this purpose I use a Newmann boundary condition with G = constant. Is that correct?
At the boundary 1, the derivative of c must be equal to zero. That why I set the weak term beeing equal to 'test(cx)'. Is that the correct way to obtain the derivative beeing equal to zero at the boundary 1? Why is it not possible to turn off the coefficient boundary conditions (Neumann and Dirichlet)?
Thank a lot in advance for your help.

Magalie Huttin

0 Replies Last Post 2010年4月20日 GMT-4 09:09
COMSOL Moderator

Hello Magalie Huttin

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