| Author | Message | ||
     Yasuo Hira (jun) New member Username: jun Post Number: 2 Registered: 12-2007 |
I want to solve the time-dependent problem that has different initial values. Is it possible to set initial value for different regions. Such as, -------------------------------------------------------------------------------- ---------------------------- INITIAL VALUES Cfe = 0.000 Ccl = 563 Co2 = 0.25 REGION 1 START (0.000, 0.030) LINE TO (0.050, 0.030) TO (0.050, 0.000) TO (0.053, 0.000) TO (0.053, 0.030) TO (0.103, 0.030) TO (0.103, 0.060) TO (0.000, 0.060) TO CLOSE Co2 = 0 REGION 2 START (0.050, 0.030) TO (0.050, 0.000) TO (0.053, 0.000) TO (0.053, 0.030) TO CLOSE -------------------------------------------------------------------------------- ------------------------------ This script (only Initial Values part has described) will cause an error, but you might understand my intention. I appreciate if you will advice how to describe this problem. | ||
| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 1011 Registered: 06-2003 |
Define a name to control the initial value selection. For example: DEFINITIONS Cswitch = Cdefault Then assign the Initial value: INITIAL VALUE C = Cswitch Now in your domain layout, you can assign different values to Cswitch in each region: BOUNDARIES REGION 1 Cswitch = C1 ... REGION 2 Cswitch = C2 In any Region where Cswitch is not redefined, the iniital value of C will be Cdefault. Bear in mind that discontinuous initial values are physically unrealastic, and can cause a strong early transient wave, forcing small mesh cells and tiny timesteps until the discontinuity is smoothed out. FlexPDE applies a mesh refinement process to help define such jumps, and an early smoothing of initial value data at such interfaces. You can control these processes with the "INITIGRIDLIMIT" and "SMOOTHINIT" Selectors. (See these names in the Help Index). | ||
| Yasuo Hira (jun) Member Username: jun Post Number: 4 Registered: 12-2007 |
Mr. Nelson I'll try above scrimption method. Yesterday, I found the other thread in the Forum. "Initial values" posted by Francesca Posted on Wednesday, February 04, 2004 - 07:16 am: Thank you for your kindness and quick support. |