ACPOWER
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.
Format
ACPOWER (format) = option
Definitions
Argument  Options  Description 

format  <H3D, PUNCH, blank>  
option  <YES, ALL, NO, NONE> 

Comments
 The result is output for every PANELG entry whose type is ACPOWER. In this case, PANELG also accommodates a SURF entry.
 Multiple formats are allowed on the same entry; these should be commaseparated. 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
(${R}_{e}$
) of acoustic intensity
$\underset{\_}{I}\left(\Omega \right)$
.
(1) Where,$$P={\displaystyle \underset{s}{\int}\mathrm{Re}}\left[\underset{\_}{I}\left(\Omega \right)\right]\cdot \underset{\_}{n}\mathrm{d}\text{}S$$ $S$
 Surface area of the panel
 $n$
 Local normal of the surface
The expression for acoustic intensity is related to the nodal pressure ( $p$ ) and the complex conjugate of the particle velocity ( $\nu *$ ), given by:(2) $$\underset{\_}{I}\left(\Omega \right)=\frac{1}{2}p\underset{\_}{v}*$$  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.
(3) $$ACPOWER\left(dB\right)=10*{\mathrm{log}}_{10}\left(\frac{ACPOWER}{ACPREFDB}\right)$$Where, $ACPOWER\text{}(db)$
 Acoustic power in decibels.
 $ACPREFDB$
 Reference acoustic power value specified using PARAM,ACPREFDB.