Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
2 juil. 2012, 07:05 UTC−4
Hi Sun Ung Kim,
I did not go through your model files but what you are observing might be related to the fact that mathematical equations which are equivalent on the continuous level, i.e., in their analytic form, may show a different behaviour/solution if you a apply a discrete numeric scheme. In particular, the discretized equations are usually no longer equivalent.
It's been a while but I worked on very similar problems a couple of years ago. Maybe this one can give you some idea on how much a solution may vary depending on the actual formulation used for the implementation.
www.comsol.com/papers/4887/download/Weddemann.pdf
Hi Sun Ung Kim,
I did not go through your model files but what you are observing might be related to the fact that mathematical equations which are equivalent on the continuous level, i.e., in their analytic form, may show a different behaviour/solution if you a apply a discrete numeric scheme. In particular, the discretized equations are usually no longer equivalent.
It's been a while but I worked on very similar problems a couple of years ago. Maybe this one can give you some idea on how much a solution may vary depending on the actual formulation used for the implementation.
http://www.comsol.com/papers/4887/download/Weddemann.pdf
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
11 juil. 2012, 23:57 UTC−4
Thank you for your reply. Probably my problem is different from what you were looking at.
My problem is solved by changing quadratic Lagrange shape function to Hermite shape functions.
Thanks anyway, and have a good day!
Best,
Sun Ung Kim
Received message from COMSOL:
Dear Sun Ung,
The difference in results is because second-order derivative terms in the f
coefficient are not accurately represented when using quadratic Lagrange
shape functions. One workaround is to change the discretization to use
Hermite shape functions instead, see attached model.
With best regards,
Thank you for your reply. Probably my problem is different from what you were looking at.
My problem is solved by changing quadratic Lagrange shape function to Hermite shape functions.
Thanks anyway, and have a good day!
Best,
Sun Ung Kim
Received message from COMSOL:
Dear Sun Ung,
The difference in results is because second-order derivative terms in the f
coefficient are not accurately represented when using quadratic Lagrange
shape functions. One workaround is to change the discretization to use
Hermite shape functions instead, see attached model.
With best regards,