Using time_interval to output a constant dt file while using an adaptive time stepper

[mariagodr]

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Question

Hi,

I modified the modules/phase_field/examples/grain_growth/3D_6000_gr.i file to simulate 3D grain growth with 1000 grains. I kept the [./TimeStepper] block to use an adaptive time stepper. As a result, the simulation outputs (Excel and Exodus files) were written with a different Δt at each time step.
However, I would like to know if it is possible to obtain Excel and Exodus outputs with a constant Δt, so that the physical time increases uniformly.

I looked through many example files on the MOOSE website and found the following two pages helpful.
(page1) https://mooseframework.inl.gov/syntax/Outputs/index.html#advanced-output
(page2) https://mooseframework.inl.gov/source/times/TimeIntervalTimes.html

"time_step_interval" command (page 1) is not quite what I could use because the dt is still not constant. So, I tried "time_interval" command (page 2) by imitating modules/thermal_hydraulics/test/tests/problems/three_pipe_shock/three_pipe_shock.i

This is how I added to my input file. I used time_interval in [Times] block.
"""
[Executioner]
type = Transient
scheme = bdf2
solve_type = PJFNK #Preconditioned JFNK (default)
petsc_options_iname = '-pc_type'
petsc_options_value = 'asm'
l_tol = 1.0e-4
l_max_its = 30
nl_max_its = 20
nl_rel_tol = 1.0e-8
start_time = 0.0
num_steps = 500
dt = 0.0002

[./TimeStepper]
type = IterationAdaptiveDT
cutback_factor = 0.9
dt = 0.0002
growth_factor = 1.1
optimal_iterations = 8
[../]

[Times]
[./output_times]
type = TimeIntervalTimes
time_interval = 1e-4
[../]
[]

[Outputs]
file_base = 1000_size2.6_1473.v3
[./exodus]
type = Exodus
sync_times_object = output_times
#time_interval = 10000 #my first attempt
#time_step_interval = 10000
[../]
[./csv]
type = CSV
[../]
[./console]
type = Console
[../]
[]
"""
However, it does not work. Could you help me with this? I know if I fix the dt I could get the results with a constant dt but my simulation will take too long so I do not want that.

Thank you for your help.

[GiudGiud]

Hello

Can you please describe how it does not work?
Is it outputting too often?

[mariagodr]

I am sorry for not sharing the error message. Here it is. When I do not add the [Time] block, it works fine.

"""Setting Up
Setting Mesh. [ 13.76 s] [ 961 MB]
Currently Setting Up Undisplaced Mesh
Preparing Mesh
Finished Updating Mesh [ 2.76 s] [ 1109 MB]
Finished Preparing Mesh [ 2.82 s] [ 1109 MB]
Finished Setting Up Undisplaced Mesh [ 2.82 s] [ 1109 MB]
Still Setting Up..

= BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES
= PID 2524 RUNNING AT 401THS3
= EXIT CODE: 9
= CLEANING UP REMAINING PROCESSES
= YOU CAN IGNORE THE BELOW CLEANUP MESSAGES

YOUR APPLICATION TERMINATED WITH THE EXIT STRING: Killed (signal 9)
This typically refers to a problem with your application.
Please see the FAQ page for debugging suggestions"""

[loganharbour]

Whenever you see signal 9 or exit code 9, it means that something external (outside of the application) killed your process.

99% of the time processes are killed because they used to much memory and the operating system killed it.

However you're running this, you should increase the memory available to the environment and try again.