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Fluid solid interaction

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  • #5640
    Gloriousface
    Participant

    Hello,

    I am using SC multicomponent model to simulate the contact angle of droplets on solid surface. Can I ask if the interaction between fluid and solid wall is realized in SC model?

    Thanks and Regards,
    Gloriousface

    #5641
    mathias
    Keymaster

    If you refer to the OpenLB examples, that is a Free Energy Model and not SC. BEst Mathias

    #5646
    Gloriousface
    Participant

    Thank you very much for your reply, but I have another question. The user guide says that the density of each component in the free energy model is the same. How can I achieve different densities?

    #5647
    savis
    Participant

    Unfortunately it’s not possible in the free energy model that’s currently implemented, and it would be quite a large undertaking to do so. If the effect of different densities is required then it would probably be easiest to implement the fluid-solid interaction in the SC model. I have discussed this before here.

    The issue back then was that an indicator for the solid is required but not accessible within the lattice coupling. So a work-around will be required if you want to take this route.

    Best,
    Sam

    #5648
    Gloriousface
    Participant

    Thank you very much for your reply.

    #5649
    Gloriousface
    Participant

    I changed the contact angle by changing the virtual density in rayleighTaylor2d, but I’m not sure whether it reflects the fluid solid force. I don’t understand why changing the virtual density and the value of force will change the contact angle? I would appreciate it if you could answer my question.

    Best
    Gloriousface

    • This reply was modified 1 year, 3 months ago by Gloriousface.
    #5667
    savis
    Participant

    To my understanding, changing the virtual density would affect the contact angle because the increased / decreased density gradient with the gas increases / decreases the solid-gas surface energy. So the solid-liquid area changes to reduce the total surface energy. This therefore affects the contact angle in a similar way to changing the fluid-solid force, which may be sufficient depending upon what you are doing.

    However, I don’t believe it truly models the interaction with the solid because this would require a Neumann boundary condition in the density rather than a Dirichlet condition. There is more detail about this in chapter 9 of ‘The Lattice Boltzmann Method: Principles and Practice’ if you are interested.

    Apologies for the delayed response.
    Sam

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