*FLUID BOUNDARY
Specify boundary conditions for fluid flow analyses.

This option is used to specify boundary conditions for fluid flow analyses. Boundary conditions can be specified as spatially varying or constant with an associated variation in time.

Products: Abaqus/CFD  Abaqus/CAE  

Type: History data

Level: Step

Abaqus/CAE: Load module

References:

Required parameters:

AMPLITUDE

Set this parameter equal to the name of the amplitude curve that defines the variation of the boundary condition magnitude during the step (Amplitude curves, Section 32.1.2 of the Abaqus Analysis User's Manual).

If this parameter is omitted, the reference magnitude is applied immediately at the beginning of the step.

OP

Set OP=MOD (default) for existing *FLUID BOUNDARYs to remain, with this option modifying existing boundary conditions or defining additional boundary conditions.

Set OP=NEW if all existing *FLUID BOUNDARYs applied to the model should be removed. New boundary conditions can be defined.

TYPE

Set TYPE=SURFACE to specify boundary values at a surface.

Set TYPE=ELEMENT to specify distributed boundary values at element faces.

Set TYPE=NODE to specify distributed boundary values at nodes.

Data lines for TYPE=SURFACE

First line:

  1. Surface label.

  2. Boundary condition type (degree of freedom) label VELX, VELY, VELZ, P, TEMP, TURBKE, TURBEPS, TURBNU, or DIST (see Active degrees of freedom” in “Boundary conditions in Abaqus/CFD, Section 32.3.2 of the Abaqus Analysis User's Manual).

  3. Boundary condition magnitude.

Repeat this data line as often as necessary to specify boundary conditions at surfaces and degrees of freedom.

Data lines for TYPE=ELEMENT

First line:

  1. Element number or element set label.

  2. Distributed boundary condition type (degree of freedom) label VELXn, VELYn, VELZn, TEMPn, TURBKEn, TURBEPSn, or TURBNUn (see Active degrees of freedom” in “Boundary conditions in Abaqus/CFD, Section 32.3.2 of the Abaqus Analysis User's Manual).

  3. Boundary condition magnitude.

Repeat this data line as often as necessary to specify fixed boundary conditions at different elements and degrees of freedom.

Data lines for TYPE=NODE

First line:

  1. Node number or node set label.

  2. Boundary condition magnitude.

Repeat this data line as often as necessary to specify fixed boundary conditions at different nodes and degrees of freedom.