Multiple Flow Regime Topology Reference

The Multiple Flow Regime Topology phase interaction model allows you to model dispersed and segregated two-phase flows within a single framework.

Table 1. Multiple Flow Regime Topology Reference
Theory	See Multiple Flow Regimes.
Example Node Path	[phase interaction] > Models > Multiple Flow Regime Topology
Requires	Physics continuum selections: Material: Multiphase Multiphase Model: Eulerian Multiphase (EMP) (Automatically activates: Multiphase Interaction, Gradients) A minimum of two phases: For each phase: Material: Gas, Liquid, Multi-Component Gas, or Multi-Component Liquid A phase interaction is required, with the second phase labelled as Multiple Flow Regime Topology.
Properties	Key properties are: Primary Phase, Secondary Phase. See Multiple Flow Regime Topology Properties.
Activates	Physics Models	The following models are activated automatically: Drag Force Multiphase Material Interaction Length Scale Interaction Area Density The following models are available in the Optional Models group box: Interphase Energy Transfer (when an energy model is activated in the physics continuum) Interphase Mass Transfer (when an energy model is activated in the physics continuum) Large Scale Interface Turbulence Damping (for a Turbulent viscous regime only) Large Scale Interface Detection Large Scale Interface Distance (when the Large Scale Interface Detection model is activated) Lift Force Surface Tension Force Turbulent Dispersion Force (for a Turbulent viscous regime only) Virtual Mass Force Wall Lubrication Force
	Model Controls (child nodes)	Flow Regime Weight Function See Flow Regime Weight Function Properties

Multiple Flow Regime Topology Properties

Primary Phase: The primary phase of the interacting pair of Eulerian phases.
Secondary Phase: The secondary phase of the interacting pair of Eulerian phas

Flow Regime Weight Function Properties

Values such as drag and heat transfer are calculated with a weighted sum of the interaction of each flow topology regime. You specify the blending function that is used in the transition between flow regimes.

Standard

The default method. The weight function for each flow topology regime is calculated as described in Standard Blending Function.

First Dispersed Regime Terminus: In the first dispersed regime, the primary phase is treated as the continuous phase. The first dispersed regime terminus is the value of the volume fraction of the secondary phase, $α_{s}$ , at which the first dispersed regime transits to the intermediate regime. The default value is 0.3.; The first dispersed regime terminus is the value $α_{f r t}$ that is used in Eqn. (1916).
Second Dispersed Regime Onset: In the second dispersed regime, the secondary phase is treated as the continuous phase. The second dispersed regime onset is the value of $α_{s}$ at which the intermediate regime transits to the second dispersed regime. The default value is 0.7.; The second dispersed regime onset is the value $α_{s r o}$ that is used in Eqn. (1917).
Blending Function Constant: The exponent that controls the width of the transition zone. This value is $B$ in Eqn. (1916) and Eqn. (1917).

Gradient Corrected Standard

A gradient based modification that leads to a smoother field of blending weight function. The weight function for each flow topology regime is calculated as described in Gradient Based Blending Function.

First Dispersed Regime Terminus: The value $α_{f r t}$ that is used in Eqn. (1919).
Second Dispersed Regime Onset: The value $α_{s r o}$ that is used in Eqn. (1920).
Blending Function Constant: The exponent that controls the width of the transition zone. This value is $B$ in Eqn. (1919) and Eqn. (1920).
Gradient Correction Factor: The factor that controls the role of the gradient in the blending function. This value is $c_{g}$ in Eqn. (1919) and Eqn. (1920). The default value is $c_{g} = 0.05$ .

User Specified

You specify the first dispersed regime and second dispersed regime blending weight functions using field functions.

First Dispersed Regime Weight Function: The field function that specifies $W_{f r}$ .
Second Dispersed Regime Weight Function: The field function that specifies $W_{s r}$ .

Flow Regime Weight Function field functions:

First Dispersed Regime Blending Weight Function of [phase interaction]: The first dispersed regime blending weight function, $W_{f r}$ in Eqn. (1916) and Eqn. (1919).
Intermediate Regime Blending Weight Function of [phase interaction]: The intermediate regime blending weight function, $W_{i r}$ in Eqn. (1918) and Eqn. (1921).
Second Dispersed Regime Blending Weight Function of [phase interaction]: The second dispersed regime blending weight function, $W_{s r}$ in Eqn. (1917) and Eqn. (1920).