Defining a surface heat flux

Display the surface heat flux load editor using one of the following methods:

• To create a new surface heat flux load, follow the procedure outlined in Creating loads (Category: Thermal; Types for Selected Step: Surface heat flux).

• To edit an existing surface heat flux load using menus or managers, see Editing step-dependent objects. To edit the region to which the load is applied, see Editing the region to which a prescribed condition is applied.

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. For this option, the magnitude you provide must be the flux per unit area.

• Select User-defined to define the magnitude of the load in user subroutine DFLUX. (This option is valid only in Abaqus/Standard analyses.) See the following sections for more information:

  • Specifying general job settings

  • DFLUX

• Select Total Flux to define a load that is uniform over the surface. For this option, the magnitude you provide must be the total magnitude of the flux applied to the surface (instead of flux per unit area).

• Select an analytical field, labeled with an (A), or a discrete field, labeled with a (D), to define a spatially varying surface heat flux. 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.)

If you selected the Uniform, Total Flux, analytical field, or discrete field distribution option, perform the following steps:

1. In the Magnitude text field, enter the surface heat flux magnitude. A positive magnitude indicates heat flow into the surface.

   For a Uniform distribution, enter the total flux magnitude divided by the surface area over which the flux is applied (units JT⁻¹L⁻²).

   For a Total Flux distribution, enter the total magnitude of the flux (units JT⁻¹). Abaqus/CAE calculates a constant uniform surface flux from the flux magnitude entered.

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.

If you selected the User-defined distribution option, perform the following steps:

1. If desired, enter the surface heat flux magnitude in the Magnitude field (units JT⁻¹L⁻²). A positive magnitude indicates heat 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.