I got a phida data with 10000 iterations. Could the phida data be reused?

Mary_Chen · August 22, 2024, 04:54

Hi, I have got a phida data with 10000 iterations, but the residual value is not low enough.
Could I continue the iterations on the basis of this phida data? Restarting the calculation takes too much time.

phoenics_cfd · August 26, 2024, 05:48

Hi, Please send the Q1 input file to CHAM's technical support team at support@cham.co.uk, and we will investigate the restart and excessive-runtime problem for you. Thank you.

Mary_Chen · August 26, 2024, 05:55

Thank you very much.

Mary_Chen · August 27, 2024, 04:42

one answer would be:

Domain settings → Initial values → Restart all variables
and set the restart file name to phida.
Change the number of iterations to xxx(number of iteration added) in the solver, then click on the CFD button to ‘Save All’ and then run the solver.

phoenics_cfd · September 2, 2024, 07:49

Hi, That is how to do the restart simulation, but the question in my mind is why after such an enormous number of iterations as 10,000, have we not secured adequate convergence?

Perhaps, too much relaxation? Perhaps, non-optimal solver and/or numerical settings? Perhaps inadequate and/or inappropriate meshing? Perhaps, some problem in the model set up?

It may be that the simulation does need in excess of 10,000 iterations for adequate convergence, but if it were me doing the simulation, investigation would be warranted, and especially to reduce the excessive runtime.

August 22, 2024, 04:54	I got a phida data with 10000 iterations. Could the phida data be reused?	#1
Mary_Chen New Member Join Date: Aug 2024 Posts: 3 Rep Power: 2	Hi, I have got a phida data with 10000 iterations, but the residual value is not low enough. Could I continue the iterations on the basis of this phida data? Restarting the calculation takes too much time.

August 26, 2024, 05:48		#2
phoenics_cfd Member michael malin Join Date: Mar 2009 Location: london Posts: 35 Rep Power: 18	Hi, Please send the Q1 input file to CHAM's technical support team at support@cham.co.uk, and we will investigate the restart and excessive-runtime problem for you. Thank you. Mary_Chen likes this.

August 27, 2024, 04:42	one answer	#4
Mary_Chen New Member Join Date: Aug 2024 Posts: 3 Rep Power: 2	one answer would be: Domain settings → Initial values → Restart all variables and set the restart file name to phida. Change the number of iterations to xxx(number of iteration added) in the solver, then click on the CFD button to ‘Save All’ and then run the solver.

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August 26, 2024, 05:55		#3
Mary_Chen New Member Join Date: Aug 2024 Posts: 3 Rep Power: 2	Thank you very much.

September 2, 2024, 07:49		#5
phoenics_cfd Member michael malin Join Date: Mar 2009 Location: london Posts: 35 Rep Power: 18	Hi, That is how to do the restart simulation, but the question in my mind is why after such an enormous number of iterations as 10,000, have we not secured adequate convergence? Perhaps, too much relaxation? Perhaps, non-optimal solver and/or numerical settings? Perhaps inadequate and/or inappropriate meshing? Perhaps, some problem in the model set up? It may be that the simulation does need in excess of 10,000 iterations for adequate convergence, but if it were me doing the simulation, investigation would be warranted, and especially to reduce the excessive runtime.