Page 244 - Process Modelling and Simulation With Finite Element Methods

Geometric Continuation 23 1
$

are now expressed as an initial condition $s = $so, BCs - = 0 and

Our FEMLAB modeling strategy is as follows:
Solve PDE once for “frozen” compaction front at position just less than 1.
1. Move the compaction front by an infinitesimal amount
2. Keep the old solvent concentration profile and update by solving PDE with
new front position
3. Go back to 1; iterate until compaction front hits bottom.
FEMLAB recipe for a single pass.

Launch FEMLAB and in the Model Navigator, select the Multiphysics tab.
Model Navigator
Select 1-D dimension
0
Select PDE modes =+ General >> time dependent, Weak solution
form
0 OK
Options/Axis settings -0.1 to 1.1, grid 0.05
Draw/Specify Geometry: bottom 0 to 0.99, top 0.99 to 1, enter points
name:front, start 0.99

Pull down the options menu and select Add/Edit constants. The AddEdit
constants dialog box appears.

AddIEdit Constants
Name of constant: theta-m Expression: 0.64
0 Name of constant: theta-0 Expression: 0.40
Name of constant: alpha Expression: theta-m/(theta-m-theta-0)
0
Name of constant: Pe Expression: 1
0 Name of constant: tau Expression: 0.01 (time step)
Name of constant: slope Expression: 0.01 (isotherm parameter)
0
APPlY
0 OK
Pull down the options menu and select Add/Edit expressions. The AddEdit
expressions dialog box appears.