# PFGRID

I/O Options EntryThe PFGRID command can be used in the I/O Options section to request output of acoustic grid participation factors for all Modal Frequency Response subcases. The output will be in the .h3d file.

## Format

PFGRID (GRIDS=setg, GRIDF=setfl, SOLUTION=setf, NULL=ipower, RPCUTOFF=rval, RPDBACUT=rpdba, CONTOUR=YES/NO,PEAKOUT) = setdof/PEAKOUT

## Examples

PFGRID(SOLUTION=391)=12
PFGRID(GRIDS=12,PEAKOUT)=23
PFGRID(GRIDF=34,PEAKOUT)=PEAKOUT

## Definitions

Argument Options Description
setg <ALL, NONE, SID>
ALL
Output acoustic grid participation for all structural grid points at the fluid-structure interface.
NONE (Default)
Do not output acoustic grid participation for any structural grid points.
SID
Output acoustic grid participation factors for a set of grids. SID refers to the ID of a SET of type GRID.
setfl <ALL, NONE, SID>
ALL (Default)
Output acoustic grid participation for all fluid grid points at the fluid-structure interface.
NONE
Do not output acoustic grid participation for any fluid grid points.
SID
Output acoustic grid participation factors for a set of grids. SID refers to the ID of a SET of type GRID.
setf <ALL, SID>
ALL (Default)
Participation factors are processed for all excitation frequencies.
SID
Participation factors are only processed for a set of excitation frequencies. SID refers to the ID of a SET of type FREQ.
ipower <INTEGER>

Default = 30

When the magnitude of a grid participation is below 10 to the minus ipower, the grid participation will not be output. Therefore, if the grid participation is less than 10-ipower, the result output for this grid will be skipped.
rval <REAL>

Default = 0.0

The grid participation will be calculated at the excited frequencies when the magnitude of the pressure is above rval. The excitation frequency will be a subset of setf.
rpdba <Non-Negative REAL>

Default = 0.0

RPDBACUT is the decibel pressure cutoff value for fluid responses and is similar to RPCUTOFF. It will take precedence over RPCUTOFF for fluid responses. A weighting is applied to RPDBACUT values at the excitation frequency. The grid participation will be calculated when the magnitude of the response is about the cutoff value. 4
CONTOUR (YES/NO)
YES (Default)
The area projected value for the fluid grid participation is output. Otherwise, the output of fluid grid participation would be the actual complex value.
peakout If peakout is present as an option inside the parenthesis of the PFGRID data, the filtered frequencies from the PEAKOUT data will be considered for output of grid participation.
setdof/PEAKOUT <SID/PEAKOUT> Degrees-of-freedom for which the grid participation factors are to be processed. SID refers to the ID of a SET of type GRID.
If PEAKOUT is specified instead of SID:
• Degrees-of-freedom for which the grid participation factors are to be processed will come from fluid DOFs in PEAKOUT Bulk Data.
• Filtered peak frequencies will be subcase dependent, if the multiple subcases are present.
• Filtered peak frequencies are only for fluid DOFs.

4. The dB value is calculated as $20{\mathrm{log}}_{10}\left(p/{p}_{0}\right)$ , where ${p}_{0}$ is the reference pressure. The reference pressure is dependent on the units specified on the UNITS input data. If the units are SI, the value is set as 2.0E-5 Pa. If they are CGS, it is set as 2.0E-4 barye. If they are MPa, it is set as 2.0E-11 MPa. If they are BG or EE, it is set as 4.17E-7 lbf/ft2. If no UNITS data is present, the default value is 2.0E-11 MPa.