Scaling acoustic results

Acoustic results scaling lets you manipulate results so you can analyze different acoustic applications, such as speech or machinery, and for different fluid mediums, such as air or water. You can scale results using the default dB reference value (which is retrieved from the Customer Defaults dialog box) and the default dB format value (derived from the data type), or you can specify any other values in the dB Scaling group in the respective dialog boxes.

You can select one of the following logarithmic decibel scales for computing acoustic results using the Edit Result dialog box:

dB10 Scaling

Using the dB10 option, the scaled value is computed using:

10 log 10 (I / Io)

where:

• I is the results quantity

• Io is the reference value

dB20 Scaling

Using the dB20 option, the scaled value is computed using:

20 log 10 (P / Po)

where:

• P is the results quantity

• Po is the reference value

Default reference values are:

Output	Scaling method	Default reference value
Acoustic Pressure	dB20	0.00002 N/m2
Acoustic Intensity	dB10	1.E-12 Watt/m2
Acoustic Power	dB10	1.E-12 Watt
Acoustic Particle Velocity	dB20	5.E-8 m/s
Acceleration	dB20	1.E-6 m/s2
Force	dB20	1.E-8 N

You may also set the reference value to use in the calculation. When plotting other results types, the default dB scaling is 1 using a dB20 scale.

Pressure results without dB scaling	Pressure results with dB scaling

Where do I find it?

Applying dB scaling to post views

Application	Pre/Post
Prerequisites	A Simulation file as the work part and displayed partSimcenter Nastran or Simcenter 3D Acoustics BEM as the specified solverAcoustic or Vibro-Acoustic as the specified analysis typeSimcenter 3D Noise and Vibration as the specified solverVibro-Acoustic as the specified analysis typeResults loaded
Command Finder	Edit Result
Location in dialog box	Apply dB Scaling

Applying dB scaling to XY plots

Application	Pre/Post
Prerequisites	A Simulation file as the work part and displayed partXY plot in the graphics window
Graphics window	Double-click any axis
Location in dialog box	X-axis Options, Y-axis Options, Z-axis Options, or Color-axis Options dialog box→Type tab→Axis group→Axis Type

Setting the default dB reference values

Application	Pre/Post
Command Finder	Customer Defaults
Location in dialog box	Simulation→Pre/Post→General→Environment tab→Decibel (dB) References group

How do I

Plot acoustic results (FEM acoustics)

Learn more

Plotting contribution from panels, structural modes, fluid modes, and MATVs

Quick links

Command reference

Pre/Post video examples

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Scaling acoustic results, Simcenter 3D 2021.1 Series

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