How to determine time step size and Max. iterations per time step.
 

hello every one i want to ask about the thumb rules for setting the time step size and how to set the maximum number of iteration.
like i am doing multi phase analysis how i decide about setting the time step size and maximum number of coefficient loops.
Plz reply

The recommendation for most simulations is:

Convergence settings:
Min coeff loops = 1
Max coeff loops = 10
Residual and/or imbalance convergence criteria determined by sensitivity analysis

Time step settings:
Adaptive time stepping, homing in on 3-5 coeff loops per time step.
Min time step small enough you never reach it
Max time step can be used to stop excessively large time steps if you need to


This way the solver finds its own time step, and the time step size it finds is always in the acceptable from a sensitivity analysis. At least I have never seen an example when it is not.

Thanks for reply sir and your kind consideration. sir how can i perform the sensitivity analysis

Sensitivity Analysis: See post #17 on this thread for time step size https://www.cfd-online.com/Forums/cf...of-method.html