Effect of Using Unions in FEKO

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

Just a simple question: 

 

I know that creating a union between two objects in CADFeko will ensure that their meshes don't clash. That said, does creating a union have any additional effects on how the solver treats the two objects? 

 

I ask because computation times seem to be considerably longer and results quite different when nearby objects are unioned, even thought they aren't in direct contact. Is this simply due to the increase in mesh size/complexity?

 

Thanks!

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Answers

  • Johan_Huysamen
    Johan_Huysamen
    Altair Employee
    edited October 2018

    Hi sutton304803

     

    When objects are very close together, it is in general required to mesh the faces relative to the size of the gap between them. This ensures that the close interaction between the currents on these surfaces will be modeled accurately by the solver.

     

    When parts that are not touching, but are close together, are included in a Union, CADFEKO knows to correctly mesh the closely located parts more finely. I suspect that this is what you are seeing in your model. With the parts not combined in a Union, CADFEKO meshes then independently (disregarding the small gaps) and you would get incorrect results.

     

    Yes, the increased number of mesh elements would increase the computation time, but this should give you more accurate results.

     

    Kind regards,

    Johan H

  • JIF
    JIF
    Altair Employee
    edited October 2018

    Hello sutton304803,

     

    If you add your model, we can take a look and verify that this is the reason for the longer simulation times (or rather finer mesh).

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