Fluids

Fluids

how to write discrete phase sample with certain frequency in Fluent?

    • Mahdi
      Subscriber

      Hi everyone,

      Is there any way that I can have Ansy Fluent to write the discrete phase sampling (Model specific---->Discrete phase-----> Sample) with certain frequency instead of every time step? For example, by adjusting DEFINE_DPM_OUTPUT UDF?

      Thank you!

    • aitor.amatriain
      Subscriber
      As far as I am concerned, the only option is to create an injection file.
    • Rob
      Ansys Employee
      Calculation Activities has an option for "flow time" so yes, you can. The only point to consider is that Fluent will estimate which time step is closest to that value: so you may find you're getting data at slightly off the desired value.
    • Mahdi
      Subscriber
      Hi Rob Calculation activities does not have any option for sampling DPM though, unless I ask it to send data to Ensight, but i want to have a file that can be read by Matlab for further processing there.
    • Rob
      Ansys Employee
      In the GUI we have
      But I can't immediately find the option in the TUI.

    • Mahdi
      Subscriber
      Thanks again Rob for your answer, but this only write the output once, and must be done manually. For a transient calculation, I need to write the position of the particles in certain frequencies like 50 time steps automatically.
    • Rob
      Ansys Employee
      Yes, or you can risk a GUI journal. We are working on the DPM post processing, and I'll add this into the request. If we've missed the command I'll add to the thread (if I can find it when I hear about it).
    • Mahdi
      Subscriber
      Thank you Rob! It will be so great if Ansys Fluent adds such flexibilities. Recording the trajectory of particles in each time steps makes huge files that are not possible to postprocess.
    • Mahdi
      Subscriber
      Thank you Aitor for your reply!
    • Rob
      Ansys Employee
      We do have the functionality, it's a conditional TUI command so if you don't the correct options it doesn't show up.

      /display/set/particle-tracks report-to file
      /display/set/particle-tracks/history-filename "filename_%t.part"
      /display/set/particle-tracks/report-variables particle-x-position particle-y-position particle-z-position particle-diameter particle-x-velocity particle-y-velocity particle-z-velocity ()
      list can be adjusted, but I assume you want to know where the particles are & how fast they're going () closes the list
      /display/set/particle-tracks report-type step
      /display/set/particle-tracks/display? no
      /display/particle-tracks/particle-tracks particle-resid-timeinjection-0 () , ,
      replace injection-0 with whatever your injection is called. The two commas are to accept a couple of defaults

      You need the last /display line as the execute command, the other lines are to set up the output. Note, if you then display (via the GUI) you are resetting the output.
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