Abaqus Keywords Reference Manual  
How to find keyword examples

*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 parameter:

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.

Optional 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 33.1.2 of the Abaqus Analysis User's Manual).

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

DISTRIBUTION

Set this parameter equal to a label that defines the distribution used in conjunction with the PVDEP boundary type (“Distribution definition,” Section 2.8.1 of the Abaqus Analysis User's Manual). This parameter is ignored if the boundary type is not PVDEP.

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.

Data lines for TYPE=SURFACE: 

First line:

  1. Surface label.

  2. Boundary condition type label VELX, VELY, VELZ, VELXNU, VELYNU, VELZNU, P, PNU, TEMP, TURBKE, TURBEPS, TURBNU, DIST, PVDEP, or PASSIVEOUTFLOW (see “Active degrees of freedom” in “Boundary conditions in Abaqus/CFD,” Section 33.3.2 of the Abaqus Analysis User's Manual).

  3. Boundary condition magnitude when the boundary type is not PVDEP. Initial volume when the boundary type is PVDEP and the DISTRIBUTION parameter is included. This value is ignored for PASSIVEOUTFLOW.

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 label VELXn, VELYn, VELZn, TEMPn, TURBKEn, TURBEPSn, or TURBNUn (see “Active degrees of freedom” in “Boundary conditions in Abaqus/CFD,” Section 33.3.2 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.