34.3. Getting Started With the Continuous Fiber Module

The continuous fiber model is implemented by user-defined functions (UDFs) and scheme routines in Ansys Fluent. A number of UDFs are used to solve the fiber equations. When you loaded the fiber module in the previous step (Loading the Continuous Fiber Module), UDF and scheme libraries that are required by the continuous fiber model were automatically loaded. Before you can begin the process of defining your fiber model, however, you will need to perform some additional setup tasks that involve allocating user-defined memory for the UDFs and hooking an adjust UDF to Ansys Fluent. Follow the procedure below.

For more information, see the following sections:

34.3.1. User-Defined Memory and the Adjust Function Setup

Allocate user-defined memory for the model by incrementing the Number of User-Defined Memory Location to 8 in the User-Defined Memory dialog box.
User Defined → User Defined → Memory...
Important: Note that you must initialize your solution (in the Solution Initialization task page) in order for user-defined memory to be allocated properly. If you are setting up a fiber simulation based on a converged case, then you will have to reload the Ansys Fluent data file after initializing the solution.
Hook the adjust function UDF to Ansys Fluent by choosing fm_adjust::fiber from the drop-down list for Adjust in the User-Defined Function Hooks dialog box.
User Defined → User Defined → Function Hooks...

34.3.2. Source Term UDF Setup

When loading the continuous fiber module via TUI, if you answered no to presetting all fiber model-specific UDF hooks during the loading process (Loading the Continuous Fiber Module) then you will need to set source terms, individually, for each fluid zone in your model. Alternatively, you can leave the default settings (none for no source term).

For each fluid zone in your model, specify none, constant, or UDF for all of the source terms by following the procedure below:

Setup → Cell Zone Conditions

In the Cell Zone Conditions task page, select a fluid zone under Zone and click edit.... This opens the Fluid dialog box.
In the Fluid dialog box, check Source Terms and click the Source Terms tab.

For each of the source terms in the scroll list (Mass, X Momentum, and so on), click the Edit... button next to each source term to open the corresponding source dialog box. Leave the default none, or choose constant or UDF from the drop-down list. Choose the UDF in the drop-down list that corresponds to the particular source term. For example, udf fm_src_mass corresponds to the Mass source term. Use the table below (Table 34.1: Source Terms and Corresponding UDFs) as a reference guide.

Table 34.1: Source Terms and Corresponding UDFs

Mass	`udf fm_src_mass`
X Momentum or Axial Momentum	`udf fm_src_x_mom`
Y Momentum or Radial Momentum	`udf fm_src_y_mom`
Z Momentum	`udf fm_src_z_mom`
Energy	`udf fm_src_enthalpy`
discrete ordinates model	`udf fm_src_dom`

Click OK when all of the UDFs have been hooked.
Repeat this process for the remaining fluid zones in your Ansys Fluent model.
Important: If you want to include radiative interaction of the fibers with the discrete ordinate (DO) radiation model, then the appropriate source term UDF (udf fm_src_dom) will be hooked automatically when you select Fiber Radiation Interaction in the Fiber Model dialog box. You must initialize the solution (which will allocate memory for the DO model) before the fiber model will be ready to accept the fiber radiation interaction data.