[CFXer]

When using input file(.res) in CFX solver, can I use a different timescale definition file?

Now I'm trying to mesh dependency test in my simulation.

But as the number of mesh increases, Courant number increases because of the reduced element size.

So my simulation with same timescale factor does not converge well, until about 3,000 iterations, it takes about 30 hours to simulate.

In this case, I think reducing timescale factor to reduce courant number of this simulation, can I use imput file(.res) to apply different timescale factor?

In previous simulation with 3,000 iterations, its timescale factor is 0.01
and I want to use timescale factor of 0.005.

Can I use the result file with timescale factor of 0.01 to the definition file with timescale factor of 0.005?

Thank you in advance.

[ghorrocks]

For a steady state simulation the method you arrive at convergence is not important. You can use any time scale factor you like.

But it is normal for you to get convergence problems on steady state simulations as you refine the mesh. It is not because of the Courant number - it is because the finer mesh has less dissipation and small transient flow features are appearing (which were suppressed in the coarser simulations due to the additional dissipation of a coarse mesh). If you cannot get convergence using the normal tricks (use of a larger time step size) then you are forced to either:
* Consider whether your simulation is adequately converged anyway. The parameters of importance to you such as pressure drop or drag may be adequately converged despite the poor residual convergence.
* Use a transient simulation and resolve the transient features. This will be a big and slow simulation.

[CFXer]

Thank you.