These domain conditions are described for The Laminar Bubbly Flow Interface:

•The Volume Force feature adds user defined volume forces to the momentum equations for each phase. If several volume force features are added to the same domain, then the sum of all contributions are added to the momentum equations.

•The Gravity feature adds gravity contributions to the momentum equations. Gravity effects both phases. Gravity features are mutually exclusive, that is, there can only be one active gravity feature per domain.

Phase Properties

The Phase Properties feature has the material properties for the continuous and the dispersed phases. It also has settings for the solid viscosity model and the drag model. When the solid phase consists of solid particles, it also has settings for the solid pressure model.

D O M A I N S E L E C T I O N

From the Selection list, choose the domains to define for the phase properties.

M A T E R I A L S

Select the materials to use for the material properties of the continuous phase and the dispersed phase respectively (when they have the selection to take their value From material). Both the Continuous phase and Dispersed phase use the Domain material by default, which uses the material defined for the domain for the liquid or gas.

If required, select another material from the Continuous phase or Dispersed phase lists to use that material’s properties for the liquid or gas, respectively.

C O N T I N U O U S P H A S E P R O P E R T I E S

Density, Continuous Phase

The default Density, continuous phase c (SI unit: kg/m3) uses values From material. If

User defined is selected, enter another value or expression.

Dynamic Viscosity, Continuous Phase

The dynamic viscosity describes the relationship between the shear stresses in a fluid and the shear rate. Intuitively, water and air have a low viscosity, and substances often described as thick, such as oil, have a higher viscosity.

The default Dynamic viscosity, continuous phase c (SI unit: Pa·s) uses values From material. The value of the viscosity is then the value defined for the material selected in

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the Materials section for the continuous phase. Select User defined to define a different value or expression.

D I S P E R S E D P H A S E P R O P E R T I E S

Density, Dispersed Phase

The default Density, dispersed phase d (SI unit: kg/m3) uses values From material. If

User defined is selected, enter another value or expression.

Diameter of Particles/Droplets

Enter a value or expression for the Diameter of particles/droplets dd (SI unit: m). The default is 10 3 m (1 mm).

S O L I D V I S C O S I T Y M O D E L

This section is available when Solid particles is selected as the Dispersed

phase on The Euler-Euler Model, Laminar Flow Interface.

Note

Select a Solid viscosity model—Calculate from mixture velocity (the default) or User

defined.

•If User defined is selected, enter a value or expression for the Dynamic viscosity, dispersed phase d (SI unit: Pa·s). The default expression is

max(phid*0.5, 5e-4)[Pa*s].

•If Calculate from mixture velocity is selected, also choose a Mixture viscosity model— Krieger type (the default) or User defined.

-For Krieger type, enter an expression or value for the Maximum packing concentration max (unitless). The default is 0.62.

-For User defined, enter a value or expression for the Dynamic viscosity (SI unit: Pa·s)

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