Access additional variable in TRN file
 

Dear all,

Briefly:
Is there a way to access all variables from the TRN file (selected variables) in CFD POST even if they are not included in the RES file (essential)?


In detail:
I have completed a transient simulation using ANSYS CFX 14.5. In order to save time at the end of the computation and to save storage space only the essential set of variables has been stored in each RES file. For the export of transient results and statistics a list of selected variables has been defined including also wall shear components, vorticity etc.

In the end I cannot access the specified variables in the TRN file in CFD post. Is this because the solver has not written the according variables in the TRN files or because the RES file does not include them?

I supect that it is related to the variable list in the RES file, since I cannot load even the basic variables like pressure when using the DEF file in combination with the TRN files instead.

I am currently trying to run the simulation again with the standard set of variables to be included in the final RES file. However, there appears to be some problem with the simulation related to memory (code 255 during the output), which I am trying to figure out.

In the mean time: Is there another way to access all variables from the TRN file in CFD POST even if they are not included in the RES file?


Thank you and regards,
Patrick

I think what happens is CFD-Post gets the list of available variables from the res file. Then if it sees extra variables in the trn file it ignores them.

I do not know of a way to access those variables in the trn file if you don't have a res file to make CFD-Post aware of them.

Thank you for the immediate response.

The problem I am encountering when switching to the standard variable list appears to be an old friend of yours:

ERROR #001100279
c_fpx_handler: Floating point exception: Overflow.

However, this error is not encountered during the solution process (divergence), but only after the run is terminated (after variable information is displayed). I have unsuccessfully tried the following to mitigate the problem:

- increase memory allocation on cluster
- check available disk space & file size on cluster
- change number of cores to alter partitioning
- change variable list to "standard" and "full" using the solver manager
- create new DEF file and use previous RES file as initial condition
- terminate run manually in solver manager

Do you have any further insight to where the problem might be?

Thank you and regards,
Patrick

I suspect this is caused by a variable which is only evaluated at the completion of a run (Ie: so not a solution variable) having divide by zero so it only causes the problem as the run shuts down. This is diabolical to fix as you have to do the whole run to generate the issue for testing.

Have a look at the variables you are putting in the results file - especially any user variables. Could any of them have a divide by zero problem?

Your suspicion seems to be correct. The following variable lists do not make any trouble during the file creation:

- Smallest
- Essential
- Selected variables:
Mach Number,Pressure,Static Entropy,Temperature,Total Pressure in Stn Frame,Total Temperature in Stn Frame,Turbulence Eddy Dissipation,Turbulence Eddy Frequency,Turbulence Kinetic Energy,Velocity u,Velocity v,Velocity w,Vorticity in Stn Frame X,Vorticity in Stn Frame Y,Vorticity in Stn Frame Z,Wall Shear X,Wall Shear Y,Wall Shear Z,Courant Number,Density,Dynamic Viscosity,Eddy Viscosity,Static Enthalpy,Total Enthalpy,Thermal Conductivity,Rothalpy,Rotational Energy,Specific Heat Capacity at Constant Pressure,Wall Scale

Unfortunately CFX Pre did not accept some variables like the first blending function for the BSL and SST model etc. as a manually entered (without typos) selected variable. Therefore a restart from this file is not possible, but it is a feasible workaround for me to access the variables in the existing TRN files.

Thank you very much.