[ElHombreMagnifico_CFD]

Hello everyone,

I'm encountering an issue while running a simulation of a piping segment using the SIMPLE pressure-velocity coupling scheme in ANSYS Fluent. Here are the details:

- When I run the solution with a low viscosity value, the residuals oscillate after a few iterations, including the monitored parameters.
- However, when I run the same Fluent settings with a higher viscosity value, the solution converges without issues.

Monitoring Setup:
- Flux report to monitor the flow rate.
- Surface report to monitor the pressure.

Questions:
1. Causes of Residual Oscillations:
- What could be causing the residuals to oscillate at low viscosity values?
- Are there specific areas in the simulation setup or model parameters that I should investigate first?

2. Stabilizing the Solution:
- What are the best practices for stabilizing the solution when using low viscosity values in the SIMPLE scheme?
- Should I consider adjusting any specific solver settings, under-relaxation factors, or mesh refinements?

3. Monitoring Parameters:
- Are there additional parameters that I should monitor to better understand the cause of the oscillations?
- Any recommendations on how to set up effective monitoring to diagnose and resolve convergence issues?

4. General Advice:
- Any general advice or tips for troubleshooting this type of behavior in ANSYS Fluent simulations?

Thanks in advance for your help!