forceModel_periodicPressure command

Syntax

Defined in couplingProperties dictionary.

forceModels
(
    periodicPressure
);
periodicPressureProps
{
    gravityFieldName "g";
    voidfractionFieldName "voidfraction";
    mode "word";
    targetVelocity vector1;
    p scalar1;
    i scalar2;
    avMixtureDensity scalar3;
};
  • g = name of gravity field

  • voidfraction = (optional, default “voidfraction”) name of voidfraction field

  • word = keyword for operation mode, choose “controlled” or “mixtureDensity”

  • vector1 = target ensemble average particle velocity (for monodisperse systems) - only for mode “controlled”

  • scalar1 = proportional constant for controller - only for mode “controlled”

  • scalar2 = integral constant for controller - only for mode “controlled”

  • scalar3 = average density of the mixture in the domain - only for mode “mixtureDensity”

Examples

forceModels
(
    periodicPressure
);
periodicPressureProps
{
    gravityFieldName "g";
    voidfractionFieldName "voidfraction";
    mode "controlled";
    targetVelocity (0. 0. 0.);
    p 2500;
    i 1;
}

Description

The force model calculates a force field following two different modi: a) “controlled” and b) “mixtureDensity”, which can be used to transform fluid pressure gradient to dynamic pressure gradient which is necessary for periodic boundaries. With modus “controlled” the force field is set in a way, that the ensemble average particle velocity reaches a target velocity. With modus “mixtureDensity”, a force field rhoMix*g*voidfraction is calculated. The force is passed to the explicitCoupleSource model via the setSourceField(..) function. For theoretical background see Radl, Girardi and Sundaresan (2012): “Effective drag law for parcel-based approaches - what can we learn from CFD-DEM?”, ECCOMAS 2012, Vienna.)

The following images show a brief summary of the equations and an overview of how the force on the CFD and DEM side is calculated:

img/forceModel_periodicPressure_1.PNG img/forceModel_periodicPressure_2.PNG img/forceModel_periodicPressure_3.PNG

Restrictions

none.