[gsh513]

Im really hoping someone can help me with this.

I am currently using FLUENT 6.3 to calculate the drag on a round faced projectile at transonic velocities. I have read that to do this i need an unsteady inviscid flow with large time steps in order for the model to assume a steady state.

there are two things i am unsure about...

1. how large is a large time step? i am running the model with a time step size of 1s for 20 steps and 100 max iterations/step (is this wrong?)

2. I set the Courant number to 0.1 (with a coupled implicit solver) as it diverged at anything larger. Is this OK?

My model dosent seem to be converging and i think it is due to one or both of the two above.

Any ideas/help/advice would be great!!