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New Particle Collision Model 0penLB 1.6

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  • #7415
    Jijo
    Participant

    Dear OpenLB community,

    I have tried the new particle collision model but I failed in validating the model with experimental studies (Single spherical Particle-wall Collision). The snippet of the code:

    // Discretization Settings
    int res = 50;
    T const charLatticeVelocity = 0.03;

    // Time Settings
    T const maxPhysT = 0.45; // max. simulation time in s
    T const iTwrite = 1E-3; // write out intervall in s

    // Domain Settings
    T const lengthX = 0.11;
    T const lengthY = 0.11;
    T const lengthZ = 0.20;

    // Fluid Settings
    T const physDensity = 1141.;
    T const physViscosity = 0.008/1141.;

    //Particle Settings
    T Radius = 10.0/1000.0;
    T const SphereDensity = 2170.;
    T const PositionX = 0.055;
    T const Positiony = 0.055;
    T const PositionZ = 0.16;

    Vector<T,3> SpherePosition = {PositionX,PositionX,PositionZ};
    Vector<T,3> SphereVelocity = {0.,0.,0.};
    Vector<T,3> externalAcceleration = {.0, .0, -9.81 * (1. – physDensity / SphereDensity)};

    // Characteristic Quantities
    T const charPhysLength = lengthX;
    T const charPhysVelocity = 0.66; // Assumed maximal velocity

    unsigned contactBoxResolutionPerDirection = 16;
    unsigned particleContactMaterial = 0;
    unsigned wallContactMaterial = 0;
    T youngsModulus = 575e6;
    T poissonRatio = 0.25;
    T dampingConstant = 0.1;
    T coefficientStaticFriction = 0.02;
    T coefficientKineticFriction = 0.3;

    /// End of the code

    The rest is similar to the settlingcube3D example. I do not see any rebound of the particle even if I increase the time step or the grid size. I read the published paper but I could not fix the issue. Any help here?

    Regards,

    #7423
    jan
    Participant

    Dear Jijo,

    as stated in [1], it is necessary to enlarge the particle for the consideration of the contact. You can do this using particle.setField<NUMERICPROPERTIES, ENLARGEMENT_FOR_CONTACT>( /* choose a value */ );. Otherwise it is to be expected that the incompressible fluid slows down the particle so that there is no contact with the wall, especially for high resolutions.

    Kind regards,
    Jan

    [1]: 10.1016/j.partic.2022.12.005

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