Fluids

Fluids

how to export a time series of instantaneous data from a LES ?

    • Emma CFD
      Subscriber
      Hello!
      I'm trying to run LES simulation in a bend pipe. In order to reduce the computational time I first run a LES simulation in a tube with periodic BC then I want to import the fluctuating velocity from the outlet of the turbulent flow and use it as an inflow BC in the bend inlet. However, I don't know how to extract a time series of instantaneous data for the velocity field any guidelines?and how to visualize the instantaneous velocity contours, I enabled the data sampling and I found that the contours of axial velocity are the same as the Unsteady statistics of the mean velocity magnitude
      Thank you!
      Regards.

    • Kalyan Goparaju
      Ansys Employee

      Hello, 

      It is not necessary to import time varying velocity to speedup an LES simulation. In fact, your precursor simulation can even just be RANS and doesn't have to be LES. Here are some LES-specific solution strategies

      https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v221/en/flu_ug/x1-107700013.17.5.html?q=LES-Specific%20Solution%20Strategies

      The only addendum is between step-1 and step-2 for your particular case - here, write-out the profile file for three velocity profiles at the inlet. Import this profile file into the u-bend case and attach it to the inlet and then start the LES run.

      With respect to visualizing the instantaneous contours - the variables that are available by default are in fact the instantaneous variables. 

      Thanks, 

      Kalyan

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