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*BOUNDARYF

Keyword type: step

This option is used to prescribe boundary conditions for 3D-fluids calculations. This includes static temperature, velocity and static pressure.

The following degrees of freedom are being used:

- 1: velocity in the local x-direction
- 2: velocity in the local y-direction
- 3: velocity in the local z-direction
- 8: static pressure
- 11: static temperature

If no *TRANSFORM card applied to the node at stake, the local directions coincide with the global ones.

Optional parameters are AMPLITUDE, TIME DELAY, and USER. Their meaning is the same as for the *BOUNDARY card.

The main differences with the *BOUNDARY card are:

- the *BOUNDARYF card can only be used within a step
- for fluids the boundary conditions are applied to element faces and not to nodes.

Thus, the cards run like:

First line:

- *BOUNDARYF
- Enter any needed parameters and their value.

Following line:

- Element number or element set label
- Local face number of the element
- First degree of freedom constrained
- Last degree of freedom constrained. This field may be left blank if only one degree of freedom is constrained.
- Actual magnitude of the prescribed displacement (default is zero)

Repeat this line if needed. For the local face numbering the reader is referred to the *DLOAD card.

    Example:

    *BOUNDARYF
    22,S3,2,2,.1

assigns to degree of freedom two of local face 3 of element 22 the value 0.1. If no transformation applies this degree of freedom corresponds to the velocity in global y-direction.

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