Question on Convergence & Stability

Altair Forum User
Altair Forum User
Altair Employee
edited October 2020 in Community Q&A

Hi All,

 

I wanted to simulate conjugate heat transfer simulation in AcuSolve which involves Conduction & Mixed convection. I have followed the best practices that are described from meshing to problem setup. Herewith, im attaching my residual plot which seems not converged and stabilized results. It would be helpful if someone help me with this.

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited May 2018

    Will you please send the .log & .inp file. And on which type of product you are working?

  • MADA
    MADA New Altair Community Member
    edited October 2019

     

    Hi, 

    I am trying to understand if my solution in Acusolve has converged or not as the maximum values for the velocity field does not fit the analytical approximation.

    Here are the residual /mass flux /density history. 

    Do I need to keep running the model?

     

    <?xml version="1.0" encoding="UTF-8"?>image.thumb.png.b83c42efd8afe1888e6c9246870e55ae.png

     

     

    <?xml version="1.0" encoding="UTF-8"?>image.thumb.png.cf59fbe7e085abef08af7667c7ddc849.png

     

     

    <?xml version="1.0" encoding="UTF-8"?>image.thumb.png.1e24f0bbc2f12d17167b5a287b1ad73b.png

  • acupro
    acupro
    Altair Employee
    edited October 2019

    What kind of simulation are you running?  What are the physics you are trying to solve?  What is the maximum expected Mach number?  Are you running this transient or steady-state?  (If transient, you may want to try increasing the max-stagger-iterations and/or decrease the time increment.)  Have you looked at the effect of refining the mesh?  Have you looked at the effect of different turbulence models?  These are the kinds of questions to be studied when determining if the approach to a simulation is adequate/correct - to qualify the simulation.

     

    Though it does appear the quantities you show have basically stabilized, they could also stabilize to an incorrect value if the modeling approach is not correct/adequate.  This may be a good case for working directly with your Altair support team.

  • MADA
    MADA New Altair Community Member
    edited October 2019

    Thank you for the questions. 

    The simulation is running to solve a steady state turbulent flow field. The mesh refinement had been implemented in the critical area of interest. The standard-K epsilon model has been chosen for the Turbulent modelling.