I/O Options and Subcase Information
Entry Used in the I/O Options section or in frequency response (direct and modal) subcases to
request acoustic power radiated across a panel for Infinite Elements and Adaptive Perfectly
Matched Layer (APML).
Format
ACPOWER (format) = option
Definitions
Argument |
Options |
Description |
format |
<H3D, PUNCH, blank> |
- H3D
- Results are output in Hyper3D format (.h3d file).
- PUNCH
- Results are output in Punch format (.pch file).
- Blank (Default)
- Results are output in all active formats for which the
result is available.
|
option |
<YES, ALL,
NO, NONE> |
- YES, ALL (Default), blank
- The acoustic power is computed for all panels defined by
PANELG with
ACPOWER type in the Bulk section.
1
- NO,
NONE
- Acoustic Power is not output.
|
Comments
- The result is output for every
PANELG entry whose type is
ACPOWER. In this case, PANELG also
accommodates a SURF entry.
- Acoustic Power results are available for Infinite Elements and Adaptive
Perfectly Matched Layer (APML). It is supported for both H3D and PUNCH
formats.
- Multiple formats are allowed on the
same entry; these should be comma-separated. If a format is not specified,
this output control applies to all formats defined by the
OUTPUT command, for which the result is
available.
- Multiple instances of this card are
allowed; if instances are conflicting, the last instance dominates.
- The acoustic power is calculated
using the surface integral of the real part (
) of acoustic intensity
. Where,
-
- Surface area of the panel
-
- Local normal of the surface
The expression for acoustic intensity is related to the nodal
pressure (
) and the complex conjugate of the
particle velocity (
), given by:
- The calculation of
ACPOWER in decibels (dB) is performed using the
PARAM, ACPREFDB, for which the following equation is
used. ACPREFDB is the reference value of the power. This
output is currently available only in PUNCH format.
Where,
-
- Acoustic power in decibels.
-
- Reference acoustic power value specified using
PARAM,ACPREFDB.