Start the unsteady computation based on the steady simulation results

Amber0922 · July 22, 2023, 10:36

Hi,
I want to start the unsteady computation based on the steady simulation results, which I think can reduce the simulation time. I think the restart can help.
But As far as I konw, the unsteay restart read the first two steps of the present step, while the steady simulation only output one restart profile.So is there any solution that can start the unsteady computation based on the steady results?

bigfootedrockmidget · July 22, 2023, 18:12

2nd order (DUAL_TIME_STEPPING-2ND_ORDER) needs 2 time steps,
1st order (DUAL_TIME_STEPPING-1ST_ORDER) needs 1 time step.

But you can copy the existing restart.dat to solution_00000.dat and solution_00001.dat to restart with a 2nd-order method.

Amber0922 · July 22, 2023, 23:23

Thank you for your generous help, I will try it again.

July 22, 2023, 10:36	Start the unsteady computation based on the steady simulation results	#1
Amber0922 Member Zhang Join Date: Mar 2023 Posts: 72 Rep Power: 3	Hi, I want to start the unsteady computation based on the steady simulation results, which I think can reduce the simulation time. I think the restart can help. But As far as I konw, the unsteay restart read the first two steps of the present step, while the steady simulation only output one restart profile.So is there any solution that can start the unsteady computation based on the steady results?

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July 22, 2023, 18:12		#2
bigfootedrockmidget Senior Member bigfoot Join Date: Dec 2011 Location: Netherlands Posts: 657 Rep Power: 19	2nd order (DUAL_TIME_STEPPING-2ND_ORDER) needs 2 time steps, 1st order (DUAL_TIME_STEPPING-1ST_ORDER) needs 1 time step. But you can copy the existing restart.dat to solution_00000.dat and solution_00001.dat to restart with a 2nd-order method.

July 22, 2023, 23:23		#3
Amber0922 Member Zhang Join Date: Mar 2023 Posts: 72 Rep Power: 3	Thank you for your generous help, I will try it again.