Is there a way to quickly achieve convergence when residuals are fluctuating!
 

Hello All,

I am using a particle tracking solver. Before injecting particles, I am running a single phase flow solution to achieve converged solution.

When I monitor my residuals(p, U), I can see they are fluctuating around 1e-02 at high Re.

In order to achieve convergence(to get residuals below ~1e-06) quickly, what necessary changes I have to make in my fvSolution.

Attached are my fvSolution and fvSchemes files.

Thanks in advance!

There are many options since this is a transient simulation. You could run it in PIMPLE mode with underRelaxation, decrease your Co number inside your controlDict, ramp up your corrector loops, set relTol to 0, lower your solution tolerance, switch to schemes that are easier to convergence like upwind for div(phi,U) or Euler for the time. Increase mesh quality etc...depends on where the low residuals are coming from. Since you are running it in single phase you could also maybe use a steady state solver.

Hello Bloerb,

I have increased the corrector loops to 4 from 2. It resulted in fall of pressure residuals.

May I know why this occur?

Also if possible, I request you to go through Posts 13 and 18 in this link and let me know about this too: https://www.cfd-online.com/Forums/op...-openfoam.html

Thanks!