[Disha11]

Hello everyone,
I am running unsteady laminar combustion simulations in ANSYS Fluent (version 2024) on an HPC cluster using a pressure-based solver.
Currently, my simulation uses a fixed time step defined in the journal file.
I would like to make the time step adaptive, so Fluent automatically adjusts it depending on convergence or flow stability.
I have already gone through the Fluent User Guide and tried the GUI-based option for “Adaptive Time Stepping”, but I need a way to enable and control it through a journal file or in batch mode since I submit jobs through a scheduler on HPC (no GUI).


My main questions are:

1. How can I enable or control adaptive time stepping using TUI commands or journal syntax?
2. Is there a way to write a Scheme script or UDF that adjusts the time step dynamically based on certain conditions?

Here’s what I’ve tried so far:

• Manually adjusting time steps in the GUI to observe how Fluent changes them under adaptive mode.
• Searching through TUI commands and Scheme files but couldn’t find documentation on adaptive time step control.
• Running small tests with fixed and varying time steps to compare convergence behavior.