Ignoring Boundary Values
Field functions access data on specific parts that are defined in the simulation. When field functions are accessed on boundary parts, two rules are used by default:
- If the data is stored on the boundary, the boundary data are accessed.
- If the data is not stored on the boundary, the cell data from the cells in the adjacent region are accessed.
In specific situations where data is stored on the boundary and in the adjacent cells, access the adjacent cell data:
- Create a user field function. See Creating a User Field Function.
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Define the new user field function such that it is defined in terms of an existing field function that is stored in both cells and on boundaries, but the values in each location differ.
An example is velocity magnitude, which has the wall velocity values stored in wall boundaries, and the wall-adjacent fluid velocity in the cells. In this case, the field function is defined as: mag($${Velocity}).
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Activate
Ignore Boundary Values in the
Expert category.
If this user field function is accessed on a boundary, it contains a scalar value corresponding to the velocity magnitude in the cell that is next to the boundary.
If the field function is applied on an interface, and the Ignore Boundary Values option is activated, the field function is computed using data from the cell next to the boundary. This data is identified using the Boundary-0 property of the interface.