34.2. Loading the Continuous Fiber Module

The continuous fiber module can be loaded only when a valid Ansys Fluent case file has been set or read.

There are two different ways in which you can load the continuous fiber module into Ansys Fluent:

Through the ribbon
In the Physics ribbon tab, click More (Models group), and select Fiber Model....
Physics → Models → More → Fiber Model...
Once the continuous fiber module is loaded into Ansys Fluent, the Fiber Model dialog box opens where you can set the model as described in Modeling Macroscopic Particles.
Through the text user interface (TUI)
The text command to load the module is
define → models → addon-module
A list of Ansys Fluent add-on modules is displayed:
```
> /define/models/addon-module 
Fluent  Addon Modules:
     0. None
     1. MHD Model
     2. Fiber Model
     3. Fuel Cell and Electrolysis Model
     4. SOFC Model with Unresolved Electrolyte
     5. Population Balance Model
     6. Adjoint Solver 
     7. Single Potential Battery Module 
     8. MSMD Battery Module 
     9. PEM Fuel Cell Model
Enter Module Number: [0] 2
```
Select the continuous fiber model by entering the module number 2. During the loading process a Scheme library containing the graphical and text user interface, and a UDF library containing a set of user-defined functions (UDFs) are loaded into Ansys Fluent.
During this process, you will be asked the question
```
 Preset all fiber model specific UDF hooks? [no] 
```
If you answer yes the standard fiber source term UDFs will be assigned to all fluid zones in your case, and a message will be reported to the console window confirming this:
```
 Assigning standard fiber source terms to all fluid zones. 
```
If you answer no to presetting source term UDFs to all fluid zones in the domain, then three options will be available to you when setting up source terms for fluid zones in your fiber model: no source, constant source, or UDF source. Note that it is your responsibility to specify the rest of the settings for a proper fiber simulation. See Source Term UDF Setup for details.
If you are loading an existing case file then you should answer the question with no. Otherwise, your saved source term settings will be replaced by a UDF.
If a mixture material has been defined, then you will be asked an additional question
```
Preset mass exchange source terms hooks? [no] 
```
If you intend to conduct a dry spinning simulation, then you should reply yes.
If you did not preset the fiber model specific UDF hooks, you will need to check allocation of user-defined memory, hook an adjust function (fm_adjust) to Ansys Fluent, and set up the source terms on your own. This is explained is User-Defined Memory and the Adjust Function Setup.

During the loading process the UDF library for the continuous fiber module is loaded in Ansys Fluent. This is reported to the console (see below). The UDF library also becomes visible as a new entry in the UDF Library Manager dialog box. The basic setup of the continuous fiber model is performed automatically when the fiber module is successfully loaded.

 Opening library "/.../addons/fiber"...
 Library "/...addons/fiber/lnx86/3d/libudf.so" opened
 fm_adjust
 fm_src_mass
 fm_src_x_mom
 fm_src_y_mom
 fm_src_z_mom
 fm_src_enthalpy
 fm_src_dom
 fm_on_demand Done.
 
 Addon Module: fiber...loaded!

Important: Note that user-defined memory locations for the fiber model will not be allocated properly if you do not initialize the flow field. If you are setting up a fiber computation based on a converged case, you must re-load the Ansys Fluent data file after initializing the solution.

The continuous fiber module setup is saved with the Ansys Fluent case file. The module is loaded automatically when the case file is subsequently read into Ansys Fluent. Note that in the saved case file, the continuous fiber module is saved with the absolute path. Therefore, if the locations of the continuous fiber module installation or the saved case file are changed, then Ansys Fluent will not be able to load the module when the case file is subsequently read. In this situation, you will have to unload the UDF library using the UDF Library Manager dialog box after the case file is read, and then reload the continuous fiber module. To unload the UDF library go to the UDF Library Manager dialog box

User Defined → User Defined → Functions → Manage...

select the fiber library under UDF Libraries, and click Unload. Previously-saved continuous fiber model setup and parameters will be preserved in this process.