time step size too small???
 

Dear all,

I have got a question concerning the proper choice of the time step size:
I run a simulation and after about 25 iterations my residuals look like this (this is an example showing about time step number 600):

Updating solution at time levels N and N-1.
done.
iter continuity x-velocity y-velocity z-velocity magnevist time/iter
! 9213 solution is converged
9213 5.5898e-14 8.0432e-15 5.2701e-15 8.5588e-15 3.8219e-04 1496884126130134:11:12 1000000000000000000
! 9214 solution is converged
9214 5.5662e-14 8.0247e-15 5.2200e-15 8.5326e-15 3.8221e-04 1498709810042426:35:44 999999999999999999
step flow-time inlet lad lcx lmca_025

The Fluent manual says that ideally there should be about 5-10 iterations per time step, otherwise one should increase the time step size.
Does it have influence on the solutions if my time step size is too small and if I have few iterations therefore?
Thank you for any help!
Lilly

If you increases the time step the number of iterations per time step increases it not should be too large approximately 0.01 s is good (be aware your solution should convergence if you increases it else you must decreases it until you get convergence) it just make your solution run faster with time.

kbaker