Learning Forum

[Seyyed Mahmoud Mousavi]

Hi!

I have 100 data files in profile format (inflow_profiles_00000.prof,...inflow_profiles_00099.prof).

Each file includes x,y,z coordinates and u,v,w flow velocity components. I want to apply these 100 profile files (from 0s to 1s with dt=0.01s) as the transient boundary condition at the inlet of my computational domain in Fluent. How I can do this? Because in Fleunt, I can read only 1 profile file at a time, but I want to apply a transient boundary condition from these 100 files.

I can provide more detail if necessary.

Thanks!

[Rob]

Transient profiles typically return a single boundary value that varies with time. So the whole boundary has the same value. 

If you really need/want to use a unique spatially varying profile at each time step then you'll need to use a journal to read the profile, attach it, do a time step & repeat.  Every time step won't be efficient, so review how much the profile changes. 

[Seyyed Mahmoud Mousavi]

Thank you Rob! I think I need to rephrase my question. I have 100 data files from experiments, in a Profile format (inflow_profiles_00000.prof...). Each data file includes the velocity profile components (u,v,w) of the same points in space but at different time steps (t=0, 0.01,...,0.99s). Now, I need to apply these velocity profiles as transient boundary conditions (velocity inlet) at the inlet plane of my computational domain. However, I do not know how to read all these 100 profile files as a single file in Fluent? Then in Fluent, I can assign these velocity profiles at the inlet of my boundary domain.

 

I hope this time I could better explain my problem.

[Seyyed Mahmoud Mousavi]

Hi Rob!

Could you please tell me more about how I can do this " you'll need to use a journal to read the profile, attach it, do a time step & repeat"? I have never worked with a journal before.

 

Thanks!

[Rob]

OK, doable but both painful and messy.  You can't combine the files, so that options not available. Transient and steady profiles have a different syntax, which can't be combined. 

How many data points do you have in each of the profiles? Ie how well resolved is the surface profile?  If you create a surface plot of x, y and variable how does it look? 

Some options then are:

• To use a journal, read & set the profile, run a time step, read & set new profile & run a time step. Repeat for some cycles. Probably slow and painful to set up and I'd question the results as you're not letting the solver stabilise due to the potential jumps in boundary value. 
• Break up the inlet into several surfaces summing to the total area and alter the profile format to give a transient profile from the many steady ones you currently have. This won't have any interpolation between faces so you may get some weird gradients. 
• Use a UDF to read all the profiles and do stuff based on one or both of the above. Doable, but I am not going to do anything other than point you at the manual. 

 

 

[Rob]

Looks like messages are passing in the system.  In Fluent the TUI commands can be written into a file to then run as a journal. In theory you can write a journal to read a mesh, set all the boundary conditions, models, solver settings etc, run the model and create all post processing. In practice we use them for repetitive tasks such as setting up 4-500 boundary conditions, or reading 100 profiles.  Click into the text window & press Enter. You'll see a command list. Type one of them and press Enter, then press Enter again. The first time activates the command, the second time shows the options available at that level. q (lower case Q) brings you up a level. So,

/file/read-case-date myfile

Should read in a case and data named myfile. 

[Seyyed Mahmoud Mousavi]

Rob, are you saying I can use TUI (or a journal?) to tell Fluent to read and assign a velocity profile file at each time step at the inlet of my computational domain? Where I can find this text window you are mentioning:

"Click into the text window(?) & press Enter. You'll see a command list. Type one of them and press Enter, then press Enter again...."

[Rob]

Sorry, the "new" name is Console, bottom right of the screenshot. The commands you build up and test in the TUI can be added into a text file to run as a journal. Pretty much all of the GUI panels have a text command equivalent, and if you type into "Quick Search" you may get the command line you need.