otherForceModel gravityEff command¶

Syntax¶

Defined in couplingProperties dictionary.

otherForceModels
(
  gravityEff
);
gravityEffProps
{
    voidfractionFieldName "voidfraction";
    rhoPart number1;
}

• voidfraction = name of the finite volume void fraction field

• number1 = particle density

Examples¶

otherForceModels
(
  gravityEff
);
gravityEffProps
{
  voidfractionFieldName "voidfraction";
  rhoPart 1500;
}

Description¶

An effective gravitational source term, gravityEff, that is necessery to drive the flow only incase of periodic box simulations. This source term is added to the momentum equation. In case of simulating periodic boxes and assuming “homogeneous no-flow condition” we will have:

This equation depicts that in “no-flow condition” static pressure gradient balances the mixture weight. Therefore, to derive the flow in periodic box simulations, a dynamic pressure gradient is defined as

If one replaces the static pressure gradient of the fluid momentum equation with

the fluid momentum equation solved in case of periodic box simulations will be

The gravityEff source term is the third term on the RHS of the momentum equation. Note that the gravitational body force of the fluid momentum equation is considered with this source term.

In the basic implementation of gravityEff, first we calculate the density of the mixture and then the source term is calculated based on the third term on the RHS of the momentum equation.

Restrictions¶

none

Related commands¶

otherForceModels