Restarting the Simulation

shailenr · December 5, 2025, 18:15

Hi Everyone,

I have a question regarding restarting simulations in CONVERGE. Is it possible to restart a simulation and adopt a different ODE solver (e.g., switch between CVODE variants) so that the new solver affects the subsequent solution?

Thank you !

alexzhangyu · December 8, 2025, 11:06

Hi,

We recommend the users not change any solver or model parameters while "restarting" a simulation. Although there are a few parameters you can change while restarting, unfortunately the ODE solver is NOT one of them.

In case you do want to change the ODE solver, if you saved a map file before the combustion happens, or before the time instance you want to change the ODE solver, then you can map start a new simulation with more freedom of changing simulation parameters.

Hope it helps.

shailenr · December 8, 2025, 18:06

Hello Dr. Zhang,

Thank you for your suggestions. I was experiencing instabilities in my simulation and wanted to see if changing the ODE solvers would help reduce the recoveries. I do see that the number of recoveries has decreased, though it hasn’t been completely eliminated.

Regarding the map file, I haven’t tried that yet, but I can give it a try.

Thank you !
Shailendra

December 5, 2025, 18:15	Restarting the Simulation	#1
shailenr New Member Shailendra Rana Join Date: May 2025 Posts: 22 Rep Power: 2	Hi Everyone, I have a question regarding restarting simulations in CONVERGE. Is it possible to restart a simulation and adopt a different ODE solver (e.g., switch between CVODE variants) so that the new solver affects the subsequent solution? Thank you !

December 8, 2025, 11:06		#2
alexzhangyu Member Yu Zhang Join Date: Oct 2021 Location: Madison Posts: 30 Rep Power: 6	Hi, We recommend the users not change any solver or model parameters while "restarting" a simulation. Although there are a few parameters you can change while restarting, unfortunately the ODE solver is NOT one of them. In case you do want to change the ODE solver, if you saved a map file before the combustion happens, or before the time instance you want to change the ODE solver, then you can map start a new simulation with more freedom of changing simulation parameters. Hope it helps. shailenr likes this. __________________ Yu Zhang, Ph.D. Senior Research Engineer, Applications Convergent Science, Inc

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December 8, 2025, 18:06		#3
shailenr New Member Shailendra Rana Join Date: May 2025 Posts: 22 Rep Power: 2	Hello Dr. Zhang, Thank you for your suggestions. I was experiencing instabilities in my simulation and wanted to see if changing the ODE solvers would help reduce the recoveries. I do see that the number of recoveries has decreased, though it hasn’t been completely eliminated. Regarding the map file, I haven’t tried that yet, but I can give it a try. Thank you ! Shailendra