Page 44 - Process Modelling and Simulation With Finite Element Methods

FEMLAB and the Basics of Numerical Analysis 31

Add/Edit Constants
Name of constant: X1
Expression: 0.0079
Apply
Name of constant: K1
Expression: 16.2
Continue with the rest of Table 1.1
OK
Now onto the Neumann boundary conditions. Pull down the Boundary menu
and select Boundary Settings.

Boundary Mode
Select domains 1 and 2 (hold down ctrl key)
Select Neumann boundary conditions

Next Subdomain mode. Pull down the Subdomain menu and select
Subdomain mode. Before setting the equations, it is useful to define some
intermediate variables to make the data entry more concise. Pull down the
options menu and select Add/Edit expressions. By experience, you should be
in Subdomain mode to add expressions for the first time.

Add/Edit Expressions
Variable name: t 1
Variable type: subdomain
Add
Repeat to create t2 through t7
Now select variable tl and click on the
definition tab.
Select level: subdomain 1
Enter expression: -Xl/(l-u*( l-l/Kl))
APPlY
Now select the variables tab, select t2, and
then click on the definition tab, and enter the
similar expression for tl , substitute index 2
where appropriate.
Continue with indices 3 through 7
0 OK