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PDE Mode, question about example Telegraph Equation (User Guide, Model library)
Posted Jun 25, 2010, 8:13 a.m. EDT 2 Replies
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Hi, everybody.
My question is about given example of modeling telegraph equation on page 169 of Model Library for COMSOL Multiphysics.
The equation is following: utt+(alpha+beta)*ut+alpha*beta*u=c^2*uxx,
and in model we define the second term not as d_a coefficient of ut, but as a right hand side, f.
Can anyone please explain the reason of this action?
Thanks in advance,
Maria.
My question is about given example of modeling telegraph equation on page 169 of Model Library for COMSOL Multiphysics.
The equation is following: utt+(alpha+beta)*ut+alpha*beta*u=c^2*uxx,
and in model we define the second term not as d_a coefficient of ut, but as a right hand side, f.
Can anyone please explain the reason of this action?
Thanks in advance,
Maria.
2 Replies Last Post Jun 25, 2010, 11:36 a.m. EDT
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Posted:
1 decade ago
Hi
Have you tried to set f=0 and da=alpha+beta ?
I believe its OK in 3.5a and 4 but might have been different in earlier versions, as the way to handle BC and initial conditions are subtily different. But I cannot now remeber why, still it seem to remind me about something.
Have you read through the book of Zimmermann ? it has nice examples to learn how to use the eqaution mode of COMSOL see the boos on comsol on the main web site, and the few thins working differently in the newer version of COMSOl is good to get you used to debug almost working models
Have fun Comsoling
Ivar
Have you tried to set f=0 and da=alpha+beta ?
I believe its OK in 3.5a and 4 but might have been different in earlier versions, as the way to handle BC and initial conditions are subtily different. But I cannot now remeber why, still it seem to remind me about something.
Have you read through the book of Zimmermann ? it has nice examples to learn how to use the eqaution mode of COMSOL see the boos on comsol on the main web site, and the few thins working differently in the newer version of COMSOl is good to get you used to debug almost working models
Have fun Comsoling
Ivar
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Posted:
1 decade ago
Dear Ivar,
I have checked now, it works perfectly both ways, thanks!
And I really appreciate the advice about the book. I need to learn how to work with PDE Mode due to some specific equations I have to solve.
All the best,
Maria.
I have checked now, it works perfectly both ways, thanks!
And I really appreciate the advice about the book. I need to learn how to work with PDE Mode due to some specific equations I have to solve.
All the best,
Maria.