Similar residuals for correct numerics?

Hi, I recently discussed in this post that if I decreased the number of absolute tolerance the residuals would look better so I did and the residuals came out very similar to the other one like this -

the little bumps are still noticeable and the p isn’t below 1 - e3, do you have any idea on how to fix this?

thank you for your time and help,
Frank Lucci

I’ve already answered this in your other post. I have not seen your particular case (as it is private) but I bet you are having some unsteady flow. Steady-state simulations where flow unsteadiness is present have a difficult time reducing the residual convergence below such values.

@jairogut should I switch to transient flow solver?

I do not know your specific simulation case but it is not always required. For example for airfoils at 10° of angle of attack, you are not going to have good convergence of p but possibly you will have a decent approximation to the lift coefficient.

@jairogut, do you think I would need transient flow for any airfoils under 5 degrees of aoa?

Hi Frank,
as @jairogut said in the other forum thread I would also consider this as “numeric noise”.
And also as long as you don’t see any clear oscillating frequency I would not consider doing a transient analysis, since those require a different approach and also can be a bit more tricky than the steady-state analysis. As long as you are not interested in transient effects and steady-state results work for you I would always first go with the steady-state simulation, which can also work well for wings depending on the wall turbulence model and the right mesh.

Best regards Sebastian