Hi.

1) If you run the simulation from the same simple initialization as your first case, than it will take approx. the same time and number of iterations.

If you decide to re-initialize your following cases with the flow result of your first predicted case, substantial computation time savings can be achieved. If you run in steady-state, pseudo-transient method with coupled solver, nevertheless approx. 2-3 characteristic throughflow times for your geometry need to be calculated again, but the pseudo-timestep can be rather large.

2) If you run in steady state and the number of iterations and mesh cells is identical, what should be any reason, that the solver should be faster than before? Essentially there is none. So it will take the same amount of time per iterations. The goal has to be to save iterations until the end result is achieved with the desired accuracy. And btw. - with coupled solver, pseudo-transient timestepping and reasonable underrelaxation factors the given 60.000 iterations look to me like a ridiculous high value and a waste of computational resources. While with the "old" SIMPLE steady-state solver is is rather the rule than the exception. Therefore the coupled solver with pseudo-transient timestepping is recommended nowadays.

3) Have you looked at the Fluent launcher (expand the "+" for additional options). It provides all necessary means to run Fluent in distributed parallel, MPI-parallelized mode on many nodes, cpu's and cores. If you are not sure about the options, please read the manual for them.

Best regards,

Dr. Th. Frank.

It will depend on the flow, turbulence model and AoA. In some cases it will converge approximately by the same time, and in others (high AoA) convergence may take much longer or not happen at all (non-regular flow separation).

Thank you very much for your reply Thomas Frank . With respect to initialization, I have introduced parametric study for velocity inlet BC, which is changed for each different case so as to compensate for AoA. As for the solving methods, I am using SIMPLE pressure-velocity coupling method and I am doing complete steady-state flow simulation and no transient flow is involved. I will look into the MPI-parallelized modes.

Sunag Rattehalli Amaranath : With initialization one usually does not refer to specificatio of boundary conditions, but to specification of an initial guess for the solution of the equation system. This can be provided by:

a) Standard initialization

b) Hybrif initialization

c) FMG initialization

d) by specifying an interpolation file

e) by restarting from an obtained solution (DAT file) without any of the methods a) through d)

You should prefer for your case method d).

Regards,

Dr. Th. Frank.