Defining Initial Mass Fraction for a Multispecies Analysis

You can define the initial mass fraction of each fluid in a multispecies analysis. Each species can be defined with a uniform concentration or a concentration that varies according to spatially mapped data.

Before you begin: You must have your spatially mapped data prepared if you want to define any species with a concentration that varies in space. The mapped data should specify different concentration values at various points in space.
Note: When you define the mass fractions of individual species using spatially mapped data, you should confirm that the relative fractions add up to 1.0 in every location you specify. The app does not perform this validation.
See Also
About Initial Mass Fractions in Multispecies Flow Simulations
In Other Guides
Defining a Fluid Domain
Creating Simulation Features
Support Selection
Defining Multispecies Section Properties
  1. From the Initial Conditions section of the action bar, click Initial Mass Fractions .
  2. Optional: Enter a Name for the initial mass fractions in the dialog box.
  3. Select the geometry supports in the model.
  4. For each species whose values are uniformly distributed in space, do the following:
    1. Select Uniform value from the distribution options.
    2. Enter a value (between 0.0 and 1.0) for the concentration of material.
  5. For each species with values that vary according to spatially mapped data, do the following:

    1. Select Mapped spatial data from the distribution options.
    2. Click Table.
      The Field Distribution dialog box opens, where you can enter or import the mapped concentration values.
    3. Choose the Data source for the mapped concentration values:

      • Table: Enter or import the mapped data into the table.

      • Referenced document: Select a 3DEXPERIENCE document that contains the mapping data. Click to search for the document in the 3DEXPERIENCE platform database. For details about the file format required, see Mapping Data File Formats.

        Changes in the referenced document are taken into account every time the simulation is run.

    4. If Data source is set to Table, specify the mapped data in the table:

      • To import the data, right-click anywhere in the table and select Import. For details about the requiredfile format required, see Mapping Data File Formats.
      • To enter the data manually, double-click in each cell and enter a value. For example, enter X-, Y-, and Z-coordinates and the corresponding concentration Value in each row of the table.

    5. Enter the Value outside the mapped region. This is a default concentration value.

      The simulation attempts to map all of the source data points and their associated concentration values onto points in the target model. For any target points where the simulation cannot map to a source point, it will substitute this default value.

    6. Select an Axis system definition for the coordinates of the mapped data values.

      • Global: Aligns the local feature triad with the global coordinate system.

      • Local: Aligns the local feature triad with a selected axis system in the model.

        Using a custom local axis system simplifies the three-dimensional definition of points in space—the X-, Y-, Z-coordinates are interpreted in the context of the local coordinate system.

    7. Select Plot Data to display symbols that indicate the locations and magnitudes of the mapped values on the model.

      Tip: If you click any row in the data table, the corresponding source point is highlighted on the model.

    8. To adjust the search control parameters, expand the Search tolerance.

      See Mapping Search Controls and Mapping Search Control Options for descriptions of these parameters.

    9. To complete the spatial mapping data assignment, click OK.
  6. To complete the initial mass fraction definition, click OK in the dialog box.
  7. To edit an initial mass fraction definition, double-click its glyph in the model. To delete an initial mass fraction definition, click its glyph and press [Delete].

    The Feature Manager can also be used to locate, edit, or delete initial mass fraction definitions.