IBParticle

Syntax

Defined in couplingProperties dictionary.

meshMotionModel IBParticle;
IBParticleProps
{
    permeability         scalar;
    integrateForce       Switch;
    alpha                scalar;
    voidfractionFieldName "voidfraction";
    insideFieldName      "inside";
    resetVoidfraction    Switch;
}

  • permeability : Additional permeability for the IB body. Scales the force with the invese of this parameter. This parameter is only considered if integrateForce false. This parameter may severely affect stability. (default: 1)

  • integrateForce : Switch how the IB force is calculated. (default: true)

  • alpha : relaxation parameter in the range [0; 1]. This parameter determines blending between current force field and the force field required to force the fluid into motion with the geometry. This parameter may severely affect stability. (default: 0.5)

  • voidfractionFieldName : name of voidfraction field (default: “voidfraction”)

  • insideFieldName : name of IB inside field (default: “inside”)

  • resetVoidfractionset complete voidfraction field to one after using it

    (default: true)

Examples

meshMotionModel IBParticle;
IBParticleProps
{
    alpha                0.5;
    voidfractionFieldName "voidfraction";
    insideFieldName      "inside";
    resetVoidfraction    true;
}

Description

The IBParticle model resolves all particles as moving object in the domain using the Immersed Boundary Method. The cell information is used from the IBvoidfraction model.

Depending on the setting for integrateForce, this model will calculate the IB force differently:

  • integrateForce true: Integrate the force over time:

    Uo = inside * ( ((-body) + 1.) * U + body * Uo)
f  = inside * f + body * alpha / dt * (Uo - U)

    This formulation of the force term performs well for low particle Reynolds or Stokes numbers.

  • integrateForce false: Under-relax the calculated force term for this time step:

    f = (1. - alpha) * f + alpha * body * (Uo - U) / ( dt * permeability )

    This formulation of the force term performs well for high particle Reynolds or Stokes numbers.

Restrictions

Currently the model is limited to cfdemSolverChem, cfdemSolverPimple, and cfdemSolverInter.

This model must be used in combination with the IBvoidfraction model.