Hi,

I trying to simulate a supersonic jet exiting from a circular nozzle, into ambient conditions. the domain length it over 100 nozzle radii long, and so the flow contians regions where the velocity scales r small. it is possible to change the time step during a run such that after the faster regions of flow converge using a small time step, the slower regions can be solved using a higher timestep other wise the convergence rates r just too slow

The simulation is being done on CFX 5.5

cheers nandu

Please read the following thread:

http://www.cfd-online.com/Forum/cfx.cgi?read=2485

Astrid

HI,

thanks for that. i have however managed to get a converged solution by stopping the simulation after ~50 timesteps with a small timestep, and then using the advection time from the intermediate result to run the simulation to a final converged solution.

thanks nandu