Fluids

Fluids

Why is water not draining from my container?

    • liamjones32
      Subscriber

      I have a circular container in an enclosure and it is not draining. These are the steps I have followed:

      • Transient model with g = -9.81m/s2
      • VOF model with implicit body force ticked
      • k-epsilon model with scalable wall functions and realizable
      • water added as a phase
      • operating density at 1.225kg/m3
      • reference pressure location = height of cylinder within the enclosure
      • Outlet at the top of the container - 'backflow volume fraction' set to 0
      • 2 outlets at the bottom of the container - 'backflow volume fraction' set at 1
      • Under solution methods, 'pressure' set to 'body force weighted' and 'turbulent kinetic energy' and 'turbulence dissipation rate' set to 'second order upwind'
      • Hybrid initialisation and volume fraction of container set to 1 (full of water)

      Please see image of set up below

      Any help would be great, thanks in advance!

    • Rob
      Ansys Employee
      What boundary conditions are in the model? Last time you asked https://forum.ansys.com/discussion/36178/why-isnt-my-fluid-transferring-from-one-container-to-the-other#latest the two volumes weren't properly connected.
    • liamjones32
      Subscriber
      Hi Rob So I have set an outlet at the top of the container with backflow volume fraction set to 0 and two outlets at the bottom of the container, as shown in the second image above, with backflow volume fraction set at 1 for both.
      Thanks

    • Rob
      Ansys Employee
      The face you set as outlet in the model should be an interior. The sides of the tank should be a wall & wall:shadow pair. At the top of the tank I'd expect either an interior (open top) or wall & wall:shadow. For the latter you may find flow takes a while to sort itself out as the system will "glug".
    • liamjones32
      Subscriber
      Thanks I'll give this a shot

    • Rob
      Ansys Employee
      Have a look at "share topology" as that might be where you're going wrong. Note, you will need to label internal wall as such because the default boundary type will be an interior.
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