### 13.1.1. Domain Interface: Basic Settings Tab

The Basic Settings tab is where you define the domain interface. It is accessible by clicking Domain Interface , or by selecting Insert > Domain Interface.

#### 13.1.1.1. Interface Type

- `Fluid Fluid`

  Connects two fluid domains or makes a periodic connection between two regions in a fluid domain.

- `Fluid Porous`

  Connects a fluid domain to a porous domain.

- `Fluid Solid`

  Connects a fluid domain to a solid domain.

- `Porous Porous`

  Connects two porous domains or makes a periodic connection between two regions in a porous domain.

- `Solid Porous`

  Connects a solid domain to a porous domain.

- `Solid Solid`

  Connects two solid domains or makes a periodic connection between two regions in a solid domain.

The interface type you select controls the domains that are available for Interface Side 1/2.

#### 13.1.1.2. Interface Side 1/2

##### 13.1.1.2.1. Domain (Filter)

The domain filter is used to filter out 2D regions that are of no interest. The drop-down list contains commonly used regions (all composite names and primitive names that are not referenced by any composites) and the extended list (displayed by clicking the Ellipsis icon) contains all regions in a domain.

##### 13.1.1.2.2. Region List

Region List 1 and Region List 2 enable the selection of regions that form each side of the interface.

#### 13.1.1.3. Interface Models

The interface model options (Translational Periodicity, Rotational Periodicity, and General Connection) each require that you specify a mesh connection method as well as specialized settings for some model options.

##### 13.1.1.3.1. Interface Model Option: Translational Periodicity

In the case of Translational Periodicity, the two sides of the interface must be parallel to each other such that a single translation transformation can be used to map Region List 1 to Region List 2. The Translational Periodicity model requires no specialized settings.

For details on the Translational Periodicity model, see Translational Periodicity in the CFX-Solver Modeling Guide.

##### 13.1.1.3.2. Interface Model Option: Rotational Periodicity

In the case of Rotational Periodicity, the two sides of the periodic interface can be mapped by a single rotational transformation about an axis. This is the most common case of periodicity and is used, for example, in the analysis of a single blade passage in a rotating machine.

If a domain interface involves rotational periodicity, the axis for the rotational transformation must also be specified in the Axis Definition area.

##### 13.1.1.3.3. Interface Model Option: General Connection

In the case of a General Connection, more options apply. The settings are described below; for information about the General Connection model, see General Connection in the CFX-Solver Modeling Guide.

###### 13.1.1.3.3.1. Frame Change/Mixing Model

###### 13.1.1.3.3.1.1. Option

- None

- Frozen Rotor

- Stage (Mixing-Plane)

- Transient Rotor-Stator

For details, see Frame Change/Mixing Model in the CFX-Solver Modeling Guide.

###### 13.1.1.3.3.1.2. Frozen Rotor: Rotational Offset Check Box

This check box determines whether or not to apply a rotational offset for one side of the interface. For details, see Rotational Offset in the CFX-Solver Modeling Guide.

When set, enter a Rotational Offset for one side of the interface.

###### 13.1.1.3.3.1.3. Stage: Pressure Profile Decay Check Box

This option affects solution stability. For details, see Pressure Profile Decay in the CFX-Solver Modeling Guide.

When set, enter a Pressure Profile Decay numerical quantity or CEL expression that specifies the rate of decay of the pressure profile.

###### 13.1.1.3.3.1.4. Stage: Downstream Velocity Constraint

For details, see Downstream Velocity Constraint in the CFX-Solver Modeling Guide.

###### 13.1.1.3.3.2. Pitch Change Options

The Pitch Change options are:

- None

  A pitch change option of `None` cannot be used for a stage interface.

- Automatic

  (applies only when Interface Models: Frame Change/Mixing Model: Option is not set to None)

- Value

  (applies only when Interface Models: Frame Change/Mixing Model: Option is not set to None)

- Specified Pitch Angles

  (applies only when Interface Models: Frame Change/Mixing Model: Option is not set to None)

For details, see Pitch Change in the CFX-Solver Modeling Guide.

###### 13.1.1.3.3.2.1. Pitch Change: Value: Pitch Ratio

Enter the pitch ratio. For details, see Value in the CFX-Solver Modeling Guide.

###### 13.1.1.3.3.2.2. Pitch Change: Specified Pitch Angles: Pitch Angle Side 1/2

Enter pitch angle for each side of the interface. For details, see Specified Pitch Angles in the CFX-Solver Modeling Guide.

Release 18.2 - © ANSYS, Inc. All rights reserved.