Learning Forum

[FrankR]

Dear Community,

the 'ANSYS Fluent Text Command List' for the FLUENT "Academic Student Release" 19.2 is listing non-existing commands.

Recently on another thread
/forum/forums/topic/path-to-command-residual-verbosity-in-text-interface/?postbadges=true

rwoolhou from ANSYS, a highly decorated member of this community, stated in the end:
"It's locked in the full version too: we do have some commands that are defunct or used for debugging builds (internal use only) so it's possibly for testing."

Now I have a similar problem:

I have to re-write my journal files from the GUI version to a version without GUI.

How do I crank up a transient simulation without GUI ?

I found somewhere
solve/dual-time-iterate number-of-timesteps max-iterations-per-timestep

In this manual, the command "dual-time-iterate" is indented identically to the commands
dpm-update
execute-commands/
initialize/

Output on my computer:

/solve>
animate/                initialize/             report-files/
cell-registers/         monitors/               report-plots/
convergence-conditions/ patch                   set/
execute-commands/       report-definitions/

/solve> dual-time-iterate
invalid command [dual-time-iterate]

So, two questions arise here:

1) Where is the command "dual-time-iterate" and "dpm-update" ? I do not need the latter one, just curious.

2) How do I crank up a transient simulation without GUI ?

   Is it correct to code
   /solve/initialize/initialize-flow
   /solve> set/number-of-time-steps 5

   And then how to continue ? And is
   /solve> set/number-of-time-steps 5
   any different from the first parameter in 
   solve/dual-time-iterate number-of-timesteps max-iterations-per-timestep
 

I use the FLUENT "Academic Student Release" 19.2 on a Windows-PC in stand-alone mode (not using Workbench).

Thank you for your advice,

FrankR

[Keyur Kanade]

for dual-time-iterate, you should set simulation as 'transient'. 

for transient please use define/model/unsteady-1st-order

[FrankR]

Dear kkanade

thanks once more, but I still do not know how to set up all parameters to start a transient simulation with TUI. I split my concerns into three sections:

 

1) When I wrote my previous posting, the follwing 11 options were available from the solve-menu:

/solve>
animate/                initialize/             report-files/
cell-registers/         monitors/               report-plots/
convergence-conditions/ patch                   set/
execute-commands/       report-definitions/

But now, a total of 14 options is available - how come ?

/solve>
animate/                initialize/             report-files/
cell-registers/         iterate                 report-plots/
convergence-conditions/ monitors/               set/
dual-time-iterate       patch                   update-physical-time
execute-commands/       report-definitions/

How can this occur ?

But "dpm-update" is still not available and should appear on the same level as "dual-time-iterate".

Dual-time-iterate IS available all of a sudden and I could invoke it.

2) I found a similar discussion on the path to commands: 
"Fluent Tui Command for transient "
https://www.cfd-online.com/Forums/fluent/116417-fluent-tui-command-transient.html

In 2013, an option "physical-time-steps" could be declared. This command is not listed in the 'ANSYS Fluent Text Command List' for the FLUENT "Academic Student Release" 19.2 .

Is it correct to code
/solve/initialize/initialize-flow
?

And then, which of these commands, or others, need to be picked for a transient simulation:

iterate
Performs a specified number of iterations.
Note
This option is still available during transient simulations, since it can be used to add more
iterations to the same time step after interrupting iterations within a time step.

 

max-iterations-per-time-step
Sets the number of time steps for a transient simulation.
Note
This option is available when automatic initialization and case modification is enabled.

number-of-time-steps
Sets the number of time steps for a transient simulation without starting the calculation.

The command
max-flow-time
Sets the maximum flow time.
is not available in the GUI under "Run Calculation".

Once all parameters are set, how do I start the transient simulation ?
As stated before, I found somewhere
solve/dual-time-iterate number-of-timesteps max-iterations-per-timestep

Which "max-iterations-per-time-step" is the one to select ? The one associated with dual-time-iterate or the single command ?

Could you be please so kind and state a complete set of commands for a transient simulation ?

3) You recommend
define/model/unsteady-1st-order

I searched both the Theory guide and the User's guide, for both "first-order unsteady" and "unsteady first-order". The search came up with exactly one match for the term "first-order unsteady" in the User's guide, chapter 29.14.2.1. The Adaptive Time Stepping Algorithm.

How do I know which option to pick from

unsteady-1st-order?
Enables/disables first-order unsteady solution model.

unsteady-2nd-order-bounded?
Enables/disables bounded second-order unsteady formulation.

Thank you so much for sharing your expertise,

FrankR

[Keyur Kanade]

1

as in previous post, dual-time-iterate is available for transient cases. tui was given in previous post to switch on transient. 

dpm update will appear in tui only when you define injection. 

2

use solve/dual-time-iterate

use no. of iterations per time step. 

3

select appropriately depending on which order you want to solve. 

you can go ahead with 2nd order. 

[FrankR]

Dearest kkanade

thank you for your persistent effort.

The list of available commands depends on the physics contained in the model. I started Fluent and got

/solve>
animate/                initialize/             monitors/
execute-commands/       iterate                 patch

Then I read in a case-file, and then:

/solve>
animate/                initialize/             report-files/
cell-registers/         iterate                 report-plots/
convergence-conditions/ monitors/               set/
dual-time-iterate       patch                   update-physical-time
execute-commands/       report-definitions/

This is so elementary. A user would appreciate to find this explained in the manual. There are scores of commands like

Use smoothed density for pseudo-transient method?
Smooths the cell density near the interface, therefore avoiding unphysical acceleration of lighter
phase in the vicinity of interface. This option is only available for steady-state pseudo-transient
method.

with a clear statement under which condition the command can be invoked. They missed it for dual-time-iterate.

I may have copied the first list of available commands in my first posting here in a situation where I had not yet read in a model.

I will be off work till next Wednesday, and am confident that your hints will solve the problem I had stated.

Sincerely

FrankR

[FrankR]

Hello

I do not get you. I pointed out what the problem was, presumably.

Make the model transient, not steady.

FrankR

[jorgeluis0395]

 Thanks for your response.

I mistakenly dual posted the question and got adviced not to do it. So I deleted this one in order the keep only one thread. 

/forum/forums/topic/solve-iterate-command-for-tui-how-to-start-a-simulation-with-tui/.

I'm sorry for that.

 

Jorge