Defining a surface concentration flux

You can create a surface concentration flux load to define a concentration flux over a surface in a mass diffusion analysis.

See Also
Creating and modifying prescribed conditions
Understanding symbols that represent prescribed conditions
The Analytical Field toolset
The Discrete Field toolset
In Other Guides
Mass Diffusion Analysis
  1. Display the surface concentration flux load editor using one of the following methods:

  2. Click the arrow to the right of the Distribution field, and select the option of your choice from the list that appears:

    • Select Uniform to define a load that is uniform over the surface.

    • Select User-defined to define the magnitude of the load in user subroutine DFLUX. See the following sections for more information:

    • Select an analytical field, labeled with an (A), or a discrete field, labeled with a (D), to define a spatially varying load. Only analytical fields and discrete fields that are valid for this load type are displayed in the selection list.

      Alternatively, you can click to create a new analytical field. (See The Analytical Field toolset for more information.)

  3. If you selected the Uniform, analytical field, or discrete field distribution option, perform the following steps:
    1. In the Magnitude text field, enter the concentration flux density (units PLT−1). A positive magnitude indicates concentration flow into the surface.
    2. If desired, click the arrow to the right of the Amplitude field, and select the amplitude of your choice from the list that appears. Alternatively, you can click to create a new amplitude. (See The Amplitude toolset for more information.)
    3. Click OK to save your data and to exit the editor.
  4. If you selected the User-defined distribution option, perform the following steps:
    1. If desired, enter the concentration flux density in the Magnitude field (units PLT−1). A positive magnitude indicates concentration flow into the surface.

      Magnitude data that you enter in the editor are passed into the user subroutine.

    2. Click OK to save your data and to exit the editor.
    3. Enter the Job module and display the job editor for the analysis job of interest. (For more information, see Creating, editing, and manipulating jobs.)
    4. In the job editor, click the General tab, and specify the file containing the user subroutine that defines the load magnitude. For more information, see Specifying general job settings.

      Note:

      You can specify only one user subroutine file in the job editor; if your analysis involves more than one user subroutine, you must combine the user subroutines into one file and then specify that file.