Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
Weak form with two dependent variables
Posted Mar 4, 2024, 9:48 a.m. EST Equation-Based Modeling Version 6.0 0 Replies
Please login with a confirmed email address before reporting spam
Hallo, I am trying to solve a Cahn-Hilliard-equation as a weak form. I am having trouble understanding how to implement the test functions. In my case the dependet variables are c and mu. Some terms are dependent on both variables. How do I implment this in the Comsol weak form PDE? The equations are:
I) dc/dt = d/dx (Dc(1-c) dmu/dx) + a*sqrt(c(1-c))*sinh(b* mu)
II) mu = ln(c/(1-c))+ d*(1-2c)-2*k*dc^2/d^2x
with the boundary condition cx = mux = 0.
The weak form should be something like with test = test function
I) int( test* dc/dt - d test/dx*Dc(1-c) d mu/dx + test* a* sqrt(c(1-c))*sinh(b*mu))dx
II) int( test* mu - test*ln(c/(1-c)-d* (1-2c))+2 k*cx *d test/dx)dx
Thank you so much for your input!
Hello Paula Lorson
Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.
If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.