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Free surface boundary conditions

OpenLB – Open Source Lattice Boltzmann Code Forums on OpenLB General Topics Free surface boundary conditions

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  • #7382
    Wolfmeister7
    Participant

    Dear OpenLB community,

    I have plans to use OpenLB for my simulation. The problem includes the following features:

    1. 2D-flow
    2. turbulent flow (up to Re=10000)
    3. bottom wall is solid, so there is no-slip boundary conditions there
    4. periodic b.c. on vertical walls
    5. free but non-deformable upper wall

    And I have two questions.

    Question number one – do I need MRT-scheme for Re=10000 or it is not obligatory and BGK will suffice?

    Question number two. There are no problems in performing b.c. 3-4, but what about free non-deformable upper wall? I do not know, how to apply them. Is it possible at all? Or should I use Shan-Chan scheme for this in order to simulate this particularly boundary condition?

    Thank you very much in advance!

    • This topic was modified 1 year, 3 months ago by Wolfmeister7.
    • This topic was modified 1 year, 3 months ago by Wolfmeister7.
    • This topic was modified 1 year, 3 months ago by Wolfmeister7.
    #7388
    mathias
    Keymaster

    1/ I would use a Smagorisky model in combination with BGK. For the free flow, I would set a Pressure BC (=Direchlet Zero for Pressure, Neumann Zero for Velocity).

    #7389
    Wolfmeister7
    Participant

    Thank you very much for your reply. I will use Smag. model with BGK.

    One more clarification. I do not know about Pressure BC in OpenLB package, can it handle the following case: v(u, w), u=dw/dy=0 on the upper boundary?
    Or Pressure BC handles it somehow different?

    #7390
    mathias
    Keymaster

    That is what pressureBC is doing.

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