How to set the solid-solid internal interface boundary condition?

granzer_22210
granzer_22210 Altair Community Member
edited July 2021 in Community Q&A

Hello,

For a CHT simulation, i know from the tutorial that at solid-fluid interface (the single interface is split in accusolve) we have to switch off the boundary condition for solid side face and keep 'wall' bc at the fluid side bc.

What about at solid-solid interface? should I switch off both the interface-surfaces at the solid-solid interface?

Thank you

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Best Answer

  • acupro
    acupro
    Altair Employee
    edited July 2021 Answer ✓

    You don't need to switch off the BC for the surface attached to the solid.  It's not needed, but causes no harm, either.  But the BC for the surface attached to the fluid is definitely needed.

    Same for the solid-solid interface.  By default (same as above) the Simple BC is type = wall with temperature_type set to flux with 0 values for heat flux and convective_heat_coefficient.  Thus the heat transfer is just the heat flux due to the temperature difference.  If you want to have additional heat flux, you can add to that with a non-zero heat flux.  Otherwise, with the default it's just perfect contact heat flux between the two solids.  You'll get BC Warnings, but those are harmless in this case.

    In both cases - fluid/solid or solid/solid - you still have just a single set of nodes at the the juncture shared by the two volumes on either side.  You don't split the nodes to have one set of nodes attached to one volume, and another set of nodes attached to the other.

Answers

  • granzer_22210
    granzer_22210 Altair Community Member
    edited July 2021

    Can anyone help me with this please?

  • acupro
    acupro
    Altair Employee
    edited July 2021 Answer ✓

    You don't need to switch off the BC for the surface attached to the solid.  It's not needed, but causes no harm, either.  But the BC for the surface attached to the fluid is definitely needed.

    Same for the solid-solid interface.  By default (same as above) the Simple BC is type = wall with temperature_type set to flux with 0 values for heat flux and convective_heat_coefficient.  Thus the heat transfer is just the heat flux due to the temperature difference.  If you want to have additional heat flux, you can add to that with a non-zero heat flux.  Otherwise, with the default it's just perfect contact heat flux between the two solids.  You'll get BC Warnings, but those are harmless in this case.

    In both cases - fluid/solid or solid/solid - you still have just a single set of nodes at the the juncture shared by the two volumes on either side.  You don't split the nodes to have one set of nodes attached to one volume, and another set of nodes attached to the other.

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