Learning Forum

[qj207]

Hi, everyone!

when I turn on the solar ray tracing model and initialize my model, there will be a message saying: 'Node 999999: Process 15040: Received signal SIGSEGV', and fluent will close by itself automatically.

Meanwhile, I found a cortexerror.log file, which says:

Error [cortex] [time 5/23/21 2:6:5] Cortex received a fatal signal (SEGMENTATION VIOLATION).

My model runs OK when I turn off the solar ray tracing model...

Could anyone help? Thank you so much in advance!

I do not have any UDFs.

[qj207]

In addition to the post, I found that the problem is in the boundary condition.
I was trying to model a double pane thermotropic glazing (the absorptivity and transmitivity of each layer of glass vary with temperature). I set the front and back glass as 'thin wall', and in the boundary condition - radiation - solar boundary condition, I try to vary the absorptivity and transmitivity using 'expression'. The expression is as follows:
IF(StaticTemperature<301.15[K],0.26,0.37)
And the problem occurs....I also tried IF(Temperaturewall<301.15[K],0.26,0.37) and IF(Temperaturewall(thin)<301.15[K],0.26,0.37)
I found that If the absorptivity and transmitivity are constant, the model runs perfectly.
Could anyone help please? Thank you so much!!!

[qj207]

I found the following in an error.log....not sure what they mean

Error [node 999999] [time 5/23/21 9:54:17] Abnormal Exit!
Node 999999 Fatal signal raised sig = Segmentation fault
2b209460 CX_Primitive_Error
a98c0cc0 seh_filter_exe
2b2ab2f0 logical_right_shift
a619eb20 _C_specific_handler
abe52060 _chkstk
abe01020 RtlRaiseException
abe50c80 KiUserExceptionDispatcher
2ae4fb70 Read_Solar_Source_Data
2ae4fb70 Read_Solar_Source_Data
2ae5bd00 Init_Solar_Flux
29d8bb70 Update_After_Flow_Init
29d8c820 Init_Flow
2981e770 init_rsubrs
2b296880 eval
2b296880 eval
2b296880 eval
2b296880 eval
2b297ee0 set_cc
2b298690 eval_errprotect
2b296880 eval
2b296880 eval
2b296880 eval
2b296880 eval
2b297ee0 set_cc
2b298690 eval_errprotect
2b20a380 CX_Interpret_String
298381a0 rpgetvar_errprotect
2b2ab2f0 logical_right_shift
ab5d7020 BaseThreadInitThunk
abe02630 RtlUserThreadStart

[Rob]

You may need to initialise the model and then turn on the expressions: the temperature data doesn't exist until the model has been initialised but the solar model needs it for it's calculation.

[qj207]

Hi Thanks for the suggestion, I did so and the initialization completed. Then I turned on the expression and run simulation, the problem happened again....

[qj207]

does the solar model have anything to do with the transmitivity/absorptivity? if as you said, why the model runs fine, when transmitivity/absorptivity are constant?

[Rob]

Solar model dumps energy into the model to avoid needing radiation as such. We also have solar ray tracing to let you calculate where the sun is to do it properly. When you add expressions/UDFs into some models the data doesn't exist to call, hence the errors.

[qj207]

Thanks for the reply! I am actually using the solar ray tracing model. I have phase change material in my model, so there are several properties, e.g., density, absorption coefficient, viscosity, etc, used expressions. It seems only the fact that transmitivity/absorptivity is expression is affecting the calculation.
I did initializing with constant transmitivity/absorptivity and then turn on the expression, but the same problem happens... Could you please suggest if there is any other solution? thank you!!!

[Rob]

Try running an iteration or time step then switching. It's possible some of the derived values are being called before they're calculated. Which version are you using as Expressions are evolving with each release.

[qj207]

Thank you for your reply, Rob! I tried as you suggested. I stopped the simulation after around 10 iterations and turn on the expression and continue the simulation. It did work for another 4 iterations, but then the same problem happened...
I am using 2021 R1, here is the detailed info:
Point Releases and Patches installed:
Academic Student 2021 R1
Aqwa 2021 R1
EnSight 2021 R1
FENSAP-ICE 2021 R1
Again, thank you so much for your time! could it be some inherent bug in this version?