Import Settings

The following settings appear under the CGNS link node when you set the Transfer Direction to Import.

[Link 1] Conditions and Values

In addition to the general conditions and values (see CGNS Link Reference), the following settings are specific to data import:

File Mode

Specifies whether Simcenter STAR-CCM+ imports data from a single file or multiple files. The available methods are:

File Series—imports data from multiple files. The files must have the same name prefix. See Base Filename.
Single File—imports data from a single file.

Timescale Control

This condition is only available if the Interval Trigger is set to Time Step or Delta Time. Allows you to control how the CGNS timescale is mapped onto the Simcenter STAR-CCM+ timescale. There are two Timescale Controls available:

Independent: Import State per Time-Step—Simcenter STAR-CCM+ timescales and CGNS timescales are independent and no data interpolation takes place.
Time Interpolated—Simcenter STAR-CCM+ timescales and CGNS timescales are adjustable. Simcenter STAR-CCM+ linearly interpolates the CGNS solution state values with respect to their corresponding time values. The specified Simcenter STAR-CCM+ start time is matched to the CGNS start time and the specified Simcenter STAR-CCM+ end time is matched to the CGNS end time.

Time Range

This condition is only available if the Interval Trigger is set to Time Step or Delta Time and allows you to either restrict the data import to a specific time range or adjust the CGNS timescale depending on the Timescale Control option selected:


Option	Timescale Control Option	Corresponding Value Nodes
Always Enabled	Independent: Import State per Time-Step The CGNS solution state data is imported at every time-step starting at the first CGNS solution state and continuing until the last CGNS solution state time.	None
Always Enabled	Time Interpolated The CGNS solution state data interpolation matches the CGNS time value to the Simcenter STAR-CCM+ timescale.	None
Enable After Start Time	Independent: Import State per Time-Step Import of the CGNS solution starts after the specified time	Start Time Specifies the Simcenter STAR-CCM+ time at which the first CGNS import occurs.
Enable After Start Time	Time Interpolated The CGNS timescale is offset so that the specified Simcenter STAR-CCM+ start time and CGNS start time align with a one-to-one time mapping.	Start Time, CGNS Start Time Specify the Simcenter STAR-CCM+ time as well as the time within the CGNS file set at which the first CGNS import occurs.
Enable Before Stop Time Only available for time-independent import.	Independent: Import State per Time-Step Data import stops at the specified time.	Stop Time Specifies the Simcenter STAR-CCM+ time at which the last CGNS import occurs.
Enable Between Start and Stop Times For the time independent mode, . For the time interpolated mode,	Independent: Import State per Time-Step Data import starts and stops at the specified times	Start Time, Stop Time Specify the Simcenter STAR-CCM+ time at which the first and last CGNS import occur.
	Time Interpolated Both the Simcenter STAR-CCM+ and CGNS timescales are adjusted so that the specified start times and stop times align. This allows for compression and expansion of the CGNS timescale.	Start Time, Stop Time, CGNS Start Time, CGNS Stop Time Specify the Simcenter STAR-CCM+ time as well as the time within the CGNS file set at which the first and last CGNS import occur.

No data is imported from the CGNS file set when either of the following conditions are met:

The current Simcenter STAR-CCM+ physical time is less than the specified Start Time.
The current Simcenter STAR-CCM+ physical time is greater than or equal to the user specified Stop Time.
Simcenter STAR-CCM+ has reached the end of the available CGNS file set import states.

Interval Trigger

Specifies the trigger method for the automatic execution of import events. The available options are:


Method	Corresponding Value Nodes
None Automatic import of CGNS data is deactivated.	None
Time Step Allows you to specify the import frequency as number of time-steps between imports.	Time Step Frequency Specifies the number of time-steps between two consecutive import events.
Delta Time Allows you to specify the time interval between imports.	Delta Time Specifies the time interval between two consecutive import events.

If Interval Trigger is set to Time Step or Delta Time there will always be an initial mesh or data import at the beginning of the simulation to set up the CGNS mesh and data even if the data import is initially disabled until a later time-step.

Mapping Option

If set to Map After Import, the CGNS data is automatically mapped to the computational domain after import. Otherwise No Mapping will occur and mapping must be triggered manually through the Data Mappers.

File

Specifies the name and location of the CGNS files to be imported:

Directory—directory in which the CGNS files are located. You can select the file directly; In this case, Simcenter STAR-CCM+ automatically updates the Base Filename and Extension properties.
Base Filename—for single file import, specifies the name of the file, without path or extension. For file series import, specifies the name prefix for the file series. For example, the files LinkExp@00001.cgns, LinkExp@00002.cgns, LinkExp@00003.cgns have the name prefix, LinkExp.
Extension—displays the file extension. Read-only.

Import Link State

Contains the solution states that Simcenter STAR-CCM+ finds in the CGNS file after performing a Scan action (see [Link 1] Right-click Actions). A solution state represents solution data at a particular time or iteration, as defined in the CGNS file. The node has the following properties:

Filename—displays the name of the imported CGNS file.
State Index—labels each state under State Name with a unique index.
State Name—allows you to select a solution state by its name. The drop down menu lists all the states found in the CGNS file with a Scan (see [Link 1] Right-click Actions). The name of a state is constructed as <Solution State Time>:<Base Filename>:<CGNS Base Node Name>.
Solution State Time—allows you to select a solution state by the CGNS solution time.
Iteration—allows you to select a solution state by the CGNS iteration number.

[Link 1] Right-click Actions

Scan: Simcenter STAR-CCM+ parses the CGNS file and retrieves the FlowSolution_t and Zone_t nodes defined in the CGNSBase_t nodes of the CGNS files. For more information on the CGNS file structure, see the official documentation, CGNS File Structure. Simcenter STAR-CCM+ indexes the CGNS FlowSolutionData_t nodes by time and/or iteration, and creates selectable solution states under the [Link] > Values > Import Link State node. See Import Link State.

Create External Parts

For each Zone_t node defined in the CGNS file, Simcenter STAR-CCM+ automatically creates:

a zone node under the [Link 1] > Zones node.
a region under the Regions node, representing the external volume zone defined in the CGNS file. This region has the same name as the corresponding zone node. The region can contain one or more boundaries:
- if the zone is a surface zone (as determined by the space model in the associated external continuum), the region contains a single boundary.
- if the zone is a volume zone, Simcenter STAR-CCM+ creates a boundary for each CGNS Elements_t node under the Zone_t node in the CGNS file.

For each zone node, Simcenter STAR-CCM+ automatically sets the External Volume Parts or External Surface Parts with the relevant regions and boundaries.

Import Meshes

Imports mesh data from the CGNS file.

Import Fields

Imports solution data from the CGNS file, for the selected solution state.

Map Import Fields

Triggers the mapping of the imported CGNS fields onto the computational domain. Only active when Mapping Option is set to Map After Import and all zones have internal Surface Parts or Volume Parts assigned to them.

[Zone] Conditions and Values

The zone conditions and values specify the external parts, defined in the CGNS file, from which Simcenter STAR-CCM+ imports data as well as the imported fields:

External Volume Parts: Specifies the volume parts in the CGNS file that are imported in Simcenter STAR-CCM+ as regions. Set automatically when executing the Create External Parts action.

External Surface Parts: Specifies the surface parts in the CGNS file that are imported in Simcenter STAR-CCM+ as boundaries. Set automatically when executing the Create External Parts action.

Imported Fields: Lists the fields that are imported within a zone. The fields are selected automatically when executing the Create External Parts action. For each field node, you can select the Field Stencil, which defines the location on the target mesh where the fields are interpolated.; The CGNS format only supports scalar fields. To define a vector, the CGNS file can specify its scalar components. To identify scalars as vector components, Simcenter STAR-CCM+ searches for the suffixes X, Y and Z in the name of the scalars. If the suffixes are present, Simcenter STAR-CCM+ imports the scalars as a single vector field. Otherwise, Simcenter STAR-CCM+ imports each component as a scalar field. When vector components are missing or empty, Simcenter STAR-CCM+ sets the corresponding components to zero in the imported vector field.
Surface Parts: Specifies the internal surface parts used when mapping the CGNS data to the computational domain. Applies when Mapping Option is set to Map After Import for surface zones.
Volume Parts: Specifies the internal volume parts used when mapping the CGNS data to the computational domain. Applies when Mapping Option is set to Map After Import for volume zones.
Import Mappers: This node is automatically created when the Imported Fields are present within the zone and the Mapping Option node is set to Map After Import. For each field node you can set the data mapper used to map the CGNS data to the computational domain. .; By default this is set to a default surface or volume mapper created when the mapping option is set to Map After Import. The Default Surface Co-Simulation Mapper 1 or Default Volume Co-Simulation Mapper 1 allows you to map the surface or volume data using the least square interpolation method. If you do not want to use the default data mapper set Mapper to a custom data mapper you have created under the Tools > Data Mappers node.