6.1.2 Hooking DEFINE_DELTAT UDFs

After you have interpreted (Chapter  4) or compiled (Chapter  5) your DEFINE_DELTAT UDF, the name of the function you supplied as a DEFINE macro argument will become visible and selectable in the Adaptive Time Step Settings dialog box (Figure  6.1.3) in ANSYS FLUENT.

To hook the UDF to ANSYS FLUENT, select Transient from the Time list in the Solver group box of the General task page.

General Transient

Then open the Run Calculation task page.

Run Calculation

Select Adaptive in the Time Stepping Method drop-down list, and click the Settings... button to open the Adaptive Time Step Settings dialog box (Figure  6.1.3).

Figure 6.1.3: The Adaptive Time Step Settings Dialog Box

Select the function name (e.g., mydeltat::libudf) in the User-Defined Time Step drop-down list and click OK.

Note that when you are using the VOF Multiphase Model, you will need to select Variable as the Time Stepping Method in the Run Calculation task page, and then hook the time step UDF in the Variable Time Step Setting dialog box in a similar manner to the Adaptive Time Step Settings dialog box.

See Section  2.2.2 for details about defining DEFINE_DELTAT functions.