controlling timestep decrease
 

Hi all,

I'm running unsteady simulations for which there's a long, uninteresting transient behavior, and then the final 10-20% are relevant. This is due to wake development and convection.

For the initial transient part I run at a timestep approximately 10 times larger than the appropriate one. Then I reduce it at the very end when the wake is formed.

My question is : is there a way to have that timestep reduced automatically while the computation runs, by changing it with a python script or whatever in the controlDict, after a predefined computation time ?

Courant-controlled timestep is useless here, and I do not want to go through a restart (this is what I'm doing right now and I'd like to change that.)

Thanks !