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TOPIC: Divergence in calculation of tidal currents

Divergence in calculation of tidal currents 5 months 2 weeks ago #43688

Hello everyone

I am trying to simulate the tidal current field in the southern part of Chile, in an area where the tidal gradient exceeds 7 meters. My scenario is forced with TXPO tidal data. My computational domain is defined in spherical coordinates duly referenced in the .cas control file.

When running the simulation, I get the following error.

ITERATION 0 TIME: 0.0000 S
TELEMAC2D INITIALIZED
USING STREAMLINE VERSION V8P4 FOR CHARACTERISTICS
EQUNOR (BIEF) : EXCEEDING MAXIMUM ITERATIONS: 500 RELATIVE PRECISION: NaN

Could you guide me to find the error and eventual solution to my problem.

Hector.



File Attachment:

File Name: Mesh02_v01_BC_2023-11-27-2.cli
File Size: 1,340 KB


File Attachment:

File Name: Mesh02_v01_T00.cas
File Size: 6 KB
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Divergence in calculation of tidal currents 5 months 2 weeks ago #43695

  • c.coulet
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Hi
I think you should take some times to well read the manuals and start to run telemac with simple case and increment complexity by steps...
According to your cas file,, without the other files (fortran and mesh), just few remarks:
  • What did you change in tpxo.f?
  • Running in FV instead of FE leads to CFL constraints. Don't have any idea of the mesh size but with a time step of 15s, this could be problematic
  • 100 of bottom smoothing :huh:

Regards
Christophe
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Divergence in calculation of tidal currents 5 months 2 weeks ago #43755

  • pham
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Hello Hector,

Every comment from Christophe is good.

Anyway, i will add 1 more advice, already written many times in this forum:
If a NaN (Not a Number) or a segmentation fault occurs, you should use a debug configuration with debug options to investigate.
See e.g. the S10.gfortran.debug configuration in the $HOMETEL/configs/systel.edf.cfg configuration file, in particular the flag fflags_debug_gfo for gfortran compiler.
fflags_debug_gfo: -g -Wall -fcheck=all -fbacktrace -fbounds-check -finit-integer=-1 -finit-real=nan -ffpe-trap=invalid,zero,overflow

It will show in which subroutine the issue/nan/segfault occurs, the first suspicious line and may help you to change something in your computation.

Hope this helps,

Chi-Tuan
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