Outputting set of .trn result files following change of B.Cs

paddywhacker · May 14, 2014, 10:08

Hi,

Using results obtained from a SS analysis, I subsequently ran a transient analysis which solved, and wrote .trn files out in the process. Solver running time was 15 days.

Having viewed the results (with which I was unhappy) I decided to change the boundary conditions slightly and re-run the transient analysis.
I did this using the .res file from the first transient simulation as the input to the solver (initial values), in order to decrease solver running time.

Although this solves much quicker, I am only able to view the final result, as the solver does not output .trn files for each timestep.

Must I conclude that the solver is only solving for the final timestep and not all timesteps up to the Total time. If this is the case, must I run the complete analysis again with the new BC's using the SS output file as the initial conditions?

The setting in CFX pre to output the .trn files (output control>output eqn residuals) was checked in both cases.

Any help is much appreciated in advance.

M

Opaque · May 14, 2014, 15:37

The ANSYS CFX solver only writes transient output files if those files are requested. You must visit the Output Control/Transient Results tab, and verify your settings.

The intermediate transient results are only stored in the transient files (nnn.trn) . The final results file only contains the information for the last computed timestep, and the information about which .trn files were written during the simulation.

paddywhacker · May 15, 2014, 05:25

Thanks for your reply.

I'm aware that transient results are stored in the transient files (nnn.trn), and that the final results file only contains the information for the last computed timestep.

However having changed the boundary conditions for transient analysis B:
i) must I re-run both a SS analysis, and a transient analysis, outputting .trn files for the transient analysis
ii) can I use the solved results from transient run A as initial values for transient run B (with new Boundary Conditions) and still output .trn files for each chosen timestep of run B, not just a final result file
iii) can I use the output results from steady state analysis A as inputs for transient run B. These have different Boundary Conditions.

Thanks

May 14, 2014, 10:08	Outputting set of .trn result files following change of B.Cs	#1
paddywhacker New Member Malcolm Join Date: Jan 2014 Location: UK / Ireland Posts: 3 Rep Power: 12	Hi, Using results obtained from a SS analysis, I subsequently ran a transient analysis which solved, and wrote .trn files out in the process. Solver running time was 15 days. Having viewed the results (with which I was unhappy) I decided to change the boundary conditions slightly and re-run the transient analysis. I did this using the .res file from the first transient simulation as the input to the solver (initial values), in order to decrease solver running time. Although this solves much quicker, I am only able to view the final result, as the solver does not output .trn files for each timestep. Must I conclude that the solver is only solving for the final timestep and not all timesteps up to the Total time. If this is the case, must I run the complete analysis again with the new BC's using the SS output file as the initial conditions? The setting in CFX pre to output the .trn files (output control>output eqn residuals) was checked in both cases. Any help is much appreciated in advance. M

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May 14, 2014, 15:37		#2
Opaque Senior Member Join Date: Jun 2009 Posts: 1,880 Rep Power: 33	The ANSYS CFX solver only writes transient output files if those files are requested. You must visit the Output Control/Transient Results tab, and verify your settings. The intermediate transient results are only stored in the transient files (nnn.trn) . The final results file only contains the information for the last computed timestep, and the information about which .trn files were written during the simulation.

May 15, 2014, 05:25		#3
paddywhacker New Member Malcolm Join Date: Jan 2014 Location: UK / Ireland Posts: 3 Rep Power: 12	Thanks for your reply. I'm aware that transient results are stored in the transient files (nnn.trn), and that the final results file only contains the information for the last computed timestep. However having changed the boundary conditions for transient analysis B: i) must I re-run both a SS analysis, and a transient analysis, outputting .trn files for the transient analysis ii) can I use the solved results from transient run A as initial values for transient run B (with new Boundary Conditions) and still output .trn files for each chosen timestep of run B, not just a final result file iii) can I use the output results from steady state analysis A as inputs for transient run B. These have different Boundary Conditions. Thanks