Fluids

Fluids

VOF single velocity field solution

    • Lugia_06
      Subscriber

      Hi everyone,

      I was using VOF to simulate a water drop falling in the air, the phase contour was working fine, however the velocity field of the water and air were not the same which should not be the case in reality. And I just found out that the assumption of VOF is solving a single momentum equation and only solve for single velocity field for the mixture. Is there a way to solve for the velocity field of water and air separately? under the inhomogenous model, Eulerian is for mixing process, I don't think it applies for water and air.

    • Raef.Kobeissi
      Subscriber
      The VOF model can model two or more immiscible fluids by solving a single set of momentum equations and tracking the volume fraction of each of the fluids throughout the domain.nThe Eulerian model on the other hand solves the momentum and continuity equation for each phase.n
    • Rob
      Ansys Employee
      Why would the water and air velocity be the same? is correct, but in your case large water droplets are modelled using VOF. n
    • Lugia_06
      Subscriber
      nVOF is solving single set of moment equation and only has one velocity field according to the Fluent theory guide 16.3 VOF theory (https://www.afs.enea.it/project/neptunius/docs/fluent/html/th/node301.htm). Is there a way to enable separate velocity for different phases?nLugia_06n
    • Rob
      Ansys Employee
      Only by using the Eulerian model: multifluid VOF. Note, if you click on Help in the 2019 & 2020 releases you'll get an up to date version of the documentation. v16 is around 5 releases old now. n
    • Lugia_06
      Subscriber
      I see... Thanks n
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