Comparison of simulations
 

Hello

I am doing 5 simulations. what i will do is to just change the velocity for every simulation and compare the outcome of the results. But what happens is that if i change the velcoity it takes more iterations to converge and also i have to reduce the convergence criteria.

Do i need to have same iterations, same residual criteria and same under relaxation factors for comparison of my simulations or Is it posisble to give a small change to these parameters as long as the surface integrals and some other convergence criterias are fulfilled?

Thank you for your time.

Mohsin

No. Iterating and using under relaxation are just a means to an end. They do not influence the solution you eventually obtain, so if your solution is actually converged, then there should be no problem.

For the same geometry, if you are modifiying the velocity, then you are modifiying also the Reynolds-number. Then you need to modify also turbulence BC (if you are in turbulent domain)
I can imagine that it takes more or less iterations to converge if you perturb the inlet BC.
But your goal is getting a converged solution, that's all.