Default value of "start_timeout" not sufficient in many scenarios

[mkvani]

✅ Before submitting

• I have searched the existing issues and did not find a duplicate.
• I am using a Python virtual environment.
• I have confirmed this is a PyFluent issue, not a problem with Ansys Fluent itself.

📝 Description of the bug

In following scenarios, it has been observed that the default value for "start_timeout" which is 60 seconds, is not sufficient:

• Fluent launch with GPU
• Fluent launch on specific machines (with low machine specifications)

Please note that this issue is not repeatable (due to inherent dependence on multiple conditions for launch time). However, this is being observed very frequently (internally and at customer site).

The problem becomes more complex because the Fluent launch failure causes Fluent processes not closing cleanly (fl_mpi processes remain open).

🔁 Steps to reproduce

import ansys.fluent.core as pyfluent

# Specify very small timeout to reproduce the issue (Fluent process not killed after failed launch)
session = pyfluent.launch_fluent(start_timeout=3)

🎯 Expected behavior

• The default value should be increased to at-least 180 seconds.
• If Fluent launch command fails, the Fluent process should be killed automatically.

💥 Actual behavior / traceback

After Fluent launch failure due to insufficient start_timeout, it leaves fl_mpi process running.

📦 PyFluent version

ansys-fluent-core = 0.37.1

🌀 Ansys Fluent version

2026 R1 (26.1)

🐍 Python version

3.10

💻 Operating system

Windows

📌 Additional context