Ansys Free Student Software

Ansys Free Student Software

Why Fluent dont calculate the low magnitude of the viscosity

    • Natali777898
      Subscriber

      Hello everyone, 

      I am trying to calculate a simple gravity VOF case (air +phase2) with the constant viscosity with the magnitude of 1e4 for the phase 2, 1 for the air. It is a 3d model(600K cells, orthogonal quality 0.4, cant make better). If my viscosity equals to 1e5 then the solution is converged, if I decrease the viscosity to 1e4, then there are 200 iterations at each time step and the solution is still not converged. I could not understand why. 

      I tried to decrease the relaxation parametres, tried to use differens schemes for volume of fraction equation. Could you please help me.

    • SRP
      Subscriber

       

      Hi,

      1) Can you please provide more information or screenshot of geometry?

      2) What is volume fraction of phase2?

      3) Please share the details of vof model and model use for phase interaction?

      3) How you patch phase 2 after initialization?

      Thank you

       

    • Natali777898
      Subscriber

      Hello, thank you very much for your response 

      1) Can you please provide more information or screenshot of geometry?

      Here is my computational domain. There is an inlet on the lower surface, from where phase 2 is extruded into the model domain, the outlet is the upper surface (blue), from where phase 1 exits the domain to guarantee the incompressibility condition.

      2) What is volume fraction of phase2?

      phase2 is the lava Volume of fraction = 1

      phase1 is the air Volume of fraction = 0

      3) Please share the details of vof model and model use for phase interaction?

      VOF model, implicite, implicite body force,Interface modelling Sharp + interfacial Anti-diffusion. I dont consider phase interaction. 

      3) How you patch phase 2 after initialization?

      I suppose that at the initial time the model domain is filled by air(phase 1), hence there is no phase 2 in the model domain.

      Thank you very much for your help!

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