### 3.4.3. Interpolation Mapping

Data from a results file can be used to initialize a simulation whose mesh is positioned, oriented, or scaled differently from the corresponding source mesh. In this case, it may be necessary to align and/or replicate results file data in order to use it for initialization. For example, you may want to use the results from several different parts of a machine that were simulated in isolation in order to initialize a simulation that involves more than one of those parts. In this case, the solution data from the results file may have to be geometrically rotated, translated, and/or scaled in order to be aligned with the corresponding part of the mesh of the simulation being initialized. As another example, you may want to use solution data from a blade passage simulation in order to initialize a blade row simulation. In this case, it is necessary to replicate the single-passage solution data in order to initialize all the blade passages of the blade row simulation. You can use interpolation mapping to align and replicate solution data as needed. You can also use interpolation mapping to selectively apply data from certain domains within a results file.

The basic procedure for setting up and using interpolation mapping is:

1. Define any transformations required for aligning results data with the mesh of the simulation being initialized.

   These transformations may include translations, rotations, and geometric scaling.

2. For the results file used for initialization, create one or more Interpolation Mapping objects as required in order to select, position, and/or replicate solution data.

   Each Interpolation Mapping object can make use of alignment transformations that you defined in the previous step. Each Interpolation Mapping object can specify that the data is replicated with uniform rotations and/or translations between each copy.

The following subsections describe each of these steps in more detail.

Note: If sequential transformations are required to move data into position, use a list of transformations within a single Interpolation Mapping object. Do not specify multiple Interpolation Mapping objects, each with one of the required transformations.

Note: Any solution data that is, after any applicable interpolation mapping, positioned outside the mesh of the case being initialized is ignored.

Note: When using interpolation mapping, all target domains must be interpolated using interpolation mapping objects. Each interpolation mapping object contains only one target domain.

The following topics are discussed.

- Defining Transformations for use in Interpolation Mapping Alignment Transformations
- Creating Interpolation Mapping Objects

#### 3.4.3.1. Defining Transformations for use in Interpolation Mapping Alignment Transformations

You can create transformations that can be used for positioning data from a results file as part of initialization.

To add a new transformation:

1. In CFX-Pre, in the tree view, right-click the Transformations object and select Insert > Transformation.

2. In the Insert Transformation dialog box, specify a name for the transformation and click OK.

   The Transformation details view appears.

3. Specify settings for the transformation and click OK.

The details view settings depend on the Transformation option:

- Rotation

  These settings work in the same way as the corresponding mesh transformation settings, described in Transformation: Rotation in the CFX-Pre User's Guide, except that the `Full Circle` option is not available and that the global coordinate frame is assumed.

- Translation

  These settings work in the same way as the corresponding mesh transformation settings, described in Transformation: Translation in the CFX-Pre User's Guide, except that the global coordinate frame is assumed.

- Scale

  These settings work in the same way as the corresponding mesh transformation settings, described in Transformation: Scale in the CFX-Pre User's Guide, except that the global coordinate frame is assumed.

Once the required Transformation objects have been defined, you are ready to use them in creating Interpolation Mapping objects.

#### 3.4.3.2. Creating Interpolation Mapping Objects

Interpolation Mapping objects can be used for selecting, positioning, and/or replicating data from a results file as part of initialization. These objects are defined on the Initial Values tabs in these locations:

- In CFX-Solver Manager in the Define Run dialog box

- In CFX-Pre in the Configuration details view

- In CFX-Pre in the Execution Control details view

To add a new Interpolation Mapping object:

1. In the details view, on the Initial Values tab, in the Interpolation Mapping section, click Add new item to the right of the list, type a name for the Interpolation Mapping object, and click OK.

2. Specify settings for the Interpolation Mapping object and click OK.

The Interpolation Mapping object settings are described here:

- Source Location: the name of the domains in the results file that require interpolation mapping

- Target Location: the name of the domain in the simulation being initialized onto which data from the source location is to be mapped

- Alignment Transformation: a list of one or more predefined transformations

  To select multiple transformations, hold the Ctrl key while selecting with the mouse button. The order in which you specify the transformations is important; transformations will be applied in the order you specify.

- Replication Control: a collection of settings for replicating the results data using repeated rotations or translations

  The `Rotation` replication control option works in the same way as the corresponding mesh transformation settings, described in Transformation: Rotation in the CFX-Pre User's Guide, except that:

  - The `Full Circle` option is not available.

  - There are two additional settings, Total Num. Instances and Theta Offset, that control the number of replications in, and the rotational offset for, the set of replicated solutions, respectively.

  The `Translation` replication control option works in the same way as the corresponding mesh transformation settings, described in Transformation: Translation in the CFX-Pre User's Guide, except that there is one additional setting, Total Num. Instances, that controls the number of replications in the set of replicated solutions.

  The `Turbo Rotation` replication control option involves settings similar to the `Rotation` replication control option, except that the angle of rotation between replications is specified indirectly: by setting Pass. in Component to the number of passages in the component mesh (the Source Location), and by setting Passages in 360 to the number of passages that reach 360° around the machine axis.

Note: If sequential transformations are required to move data into position, use a list of transformations within a single Interpolation Mapping object. Do not specify multiple Interpolation Mapping objects, each with one of the required transformations.

For each Interpolation Mapping object, the Alignment Transformation and Replication Control settings are applied in the following order:

1. If specified, alignment transformations are applied in the order listed.

2. If the Replication Control check box is selected and the replication control setting Transformation is set to `Rotation` or `Turbo Rotation`, then the Theta Offset setting is applied. Note that the Theta Offset setting effects a type of alignment transformation, but is located among the Replication Control settings for convenience.

3. If specified, replication is applied.

If available, the Theta Offset setting in the `Rotation` and the `Turbo Rotation` replication control options is applied after the alignment transformation (if available), and the replication of multiple copies (that is, Total Num. Instances) is applied in the last transformation.

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