# FSI

Bulk Data Entry Defines the settings for Fluid-Structure Interaction Analysis with AcuSolve.

## Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
FSI FSID SURFID/ELSET PORT FCNVTOL DCNVTOL TCNVTOL FXCNVTOL
MINEX MAXEX USETAG FSIDATA   WAITTIME

## Definitions

Field Contents SI Unit Example
FSID Fluid-Structure Interaction identification number.

No default (Integer > 0) 1 2 3

SURFID ID of the damp surface defined by the SURF Bulk Data Entry.

Alternatively, the surface can be defined by an element set (via ELSET field) if the surface contains only shell, bar, or beam elements.

No default (Integer > 0)

ELSET Element SET ID of the damp surface elements. These can be shell, bar or beam elements.

The SURFID field should be used if the damp surface is the surface of a solid mesh.

No default (Integer > 0)

PORT Socket Port number for communication with AcuSolve.

This should be the same as the socket_port setting in the EXTERNAL_CODE block of the AcuSolve input data

Default = 10000 (Integer > 0, or blank)

FCNVTOL Tolerance for exchange convergence of forces.

Default = 0.005 (Real > 0.0, or blank)

DCNVTOL Tolerance for exchange convergence of displacements.

Default = 0.0001 (Real > 0.0, or blank)

TCNVTOL Tolerance for exchange convergence of temperatures (for future use).

Default = 0.005 (Real > 0.0, or blank)

FXCNVTOL Tolerance for exchange convergence of heat-fluxes (for future use).

Default = 0.0001 (Real > 0.0, or blank)

MINEX Minimum number of exchanges between OptiStruct and AcuSolve per time step. 6

Default = 1 (Integer > 0, or blank)

MAXEX Maximum number of exchanges between OptiStruct and AcuSolve per time step. 6

Default = 10 (Integer > 0, or blank)

USETAG
= 0 (Default)
All the damp surfaces will be in tagged as "0"
= 1
All the damp surfaces will be tagged with PSHELL, PBEAM, or PBAR ID.
blank

Each property ID must match the TAG ID specified by the EXTERNAL_CODE_SURFACE external_code_tags data in the AcuSolve input data.

(Integer)

FSIDATA Determines the data to be exchanged between OptiStruct and AcuSolve.
= 1 (Default)
Exchange forces and displacements.
= 2
Exchange forces/moments and displacements/rotations.
= 3
Exchange temperatures and heat-fluxes.
blank

(Integer) 4

WAITTIME The time in seconds, that OptiStruct waits (after pre-processing is complete) for AcuSolve to respond.

Default = 3600 (Integer > 0, or blank)