Lift Force Model Reference

The Lift Force model is used for calculating interphase momentum transfer – the perpendicular lift force that a particle can experience in a non-uniform or swirling flow field.

Table 1. Lift Force Model Reference
Theory See Lift.
Provided By [phase interaction] > Models > Optional Models
Example Node Path [phase interaction] > Models > Lift Force
Requires
Physics continuum selections:
  • Material: Multiphase
  • Multiphase Model: Eulerian Multiphase (EMP) (Automatically activates: Multiphase Interaction, Gradients.)
  • Optional Models: Gravity

Two Eulerian phases are required.

A Continuous-Dispersed Topology or Multiple Flow Regime Topology phase interaction is required.

Phase interaction selections:
  • Optional Models: Lift Force
Properties None.
Activates Model Controls

For a Continuous-Dispersed phase interaction:

For a Multiple Flow Regime phase interaction:

  • First Dispersed Regime Lift Coefficient

  • Intermediate Regime Lift Coefficient

  • Second Dispersed Regime Lift Coefficient

    See Lift Coefficient Properties.

Field Functions

See Lift Force Field Functions.

Lift Coefficient Properties

Dimensions
Dimensionless.
Method
Selects the method to use for specifying the lift coefficient.
  • Constant
  • Field Function
  • Sugrue

    Defines the standard lift coefficient using the Sugrue correlation. This method is intended for modelling turbulent bubbly flow. In particular, this model captures the critical inversion between positive and negative lift coefficients that determines whether bubbles will migrate towards the walls in a channel or away from the walls, towards the center of the flow.

  • Tomiyama

    Defines the standard lift coefficient using the Tomiyama correlation. This option is available only when the continuous phase is viscous and the dispersed phase is a gas. Additionally, the correlation requires that gravity is activated for the physics continuum. Specify the surface tension value in the Multiphase Material > Material Properties > Surface Tension node for the parent phase interaction. The Surface Tension node appears automatically when the correlation is selected.

Lift Force Coefficient Correction

When you use drag correction in a simulation where the Lift Force model is also used, the reduction of drag force (see Eqn. (1927) and Eqn. (1930)) can render the simulation numerically unstable. To resolve this, the lift correction is used to account for multi-particle effects by modifying the single-particle lift coefficients.

The lift correction can be approximated by the drag correction, or specified by a field function. For more information, see Lift.

If the Drag Coefficient selection is a standard type (the default setting), this option is activated by default when you select the Lift Force model. However, if the Drag Coefficient selection is a linearized type, this option is deactivated and cannot be set.

Lift Correction Properties

Dimensions
Dimensionless.
Method
Selects the method to use for specifying the lift correction.
  • Field Function
  • Drag Correlated
    NoteThe Drag Correlated lift correction method is deprecated and will be removed in a future version.

    Uses the drag coefficient correction to approximate the lift coefficient correction.

    This approximation is useful for cases when swarming is modeled.

  • Podowski Near Wall Adjustment

    The Podowski Near Wall Adjustment forces the lift coefficient to zero near the wall. This method neglects wall lubrication and models only the effects of turbulent dispersion, which leads to a flat volume fraction profile in the near-wall region. In order to recover the gas fraction peak near the wall, it is recommended to activate the Wall Lubrication model.

Lift Force Field Functions

Lift Coefficient of [phase interaction]