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Divergence detected in AMG Solver : Temperature

    • sandeepruchi93
      Subscriber

      I'm a new learner in Simulation world. I'm working on solidification simulation analysis using ANSYS Fluent. I'm trying to see the temperature variation and liquid fraction with time. My domain is like a cavity in the mold. I have filled the cavity with liquid metal. Now I want to see the solidification behavior of the metal.


      I have selected the quadrilateral shape of the meshing under Hex dominant method with body sizing is 0.002 m. My mold size is approximately  56*30*20 cm3. I have completed the whole setup procedure in which residual values are 10^(-6). After 500 iterations it's showing an error like Error: Divergence detected in AMG Solver: Temperature


      What could be causing this issue and how can I solve it ?


      Best regards 


      Sandeep Jain


      PhD research scholar

    • Rob
      Ansys Employee

      Please don't use the "hex dominant" meshing method. It's designed for Mech models and produces rubbish meshes for CFD: check the skew of your mesh.  If you mean you have a mesh that is mostly hex then also check quality.  The confusion comes from the naming of the meshing method: we have raised this as it causes confusion. 


      Otherwise you also need to work through all of the model settings: divergence just means the solver is struggling so isn't overly diagnostic. 


       

    • sandeepruchi93
      Subscriber

      Hello sir


      Thanks a lot for your quick reply. can you advise me which type of mesh I can use for Ansys Fluent Solidification model?


       


      Your reply will helpful for me.

    • Rob
      Ansys Employee

      Basically anything but the "hex-dominant" mesh.  The best option is entirely dependent on the model and geometry. Polyhedrals may be suitable (via Fluent Meshing). Just be a little careful with the inflation aspect ratio. 

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