| Author | Message | ||
     Tan Hunseng (tan) Junior Member Username: tan Post Number: 3 Registered: 08-2003 |
How to set up equation for this problem?? thank you.  | ||
| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 218 Registered: 06-2003 |
First, you have to decide what you want to use for your dependent variable. You have written "e" as a function of "sigma", but the equations appear to be written in terms of "e". It is also not clear in the low-res graphic whether you have written "e"="A" times "sigma" to the power "t*B", or "A" times "sigma-prime" to the power "B". (I assume it is the latter, because otherwise the (de/dt) would collapse leaving a spatial equation depending only parametrically on t.) In any case, you will have to clear the derivatives wrt "e" by hand. While FlexPDE does extensive symbolic processing to create the Galerkin equations, it does not have a general differentiator to expand derivatives other than those wrt coordinates. Having done this, the rest of the preparation will follow directly the development shown in the FlexPDE User Guide (online at "Product Info | Tutorial"). |