Using microphone mesh to capture analysis results

Microphones are sensors at defined locations to capture acoustic results. In an acoustics model, you can define a microphone at any location and request results such as pressure, velocity, and intensity. You can create microphones on an existing mesh or from mesh primitives such as planes, spheres, and point sets.

You can create microphones in the Simcenter Nastran FEM acoustic and vibro-acoustic environment and in the Simcenter 3D Acoustics BEM environment.

Creating microphones on existing meshes

In the software, microphones are elements. You can create microphones on existing meshes as:

• A 0D element that references an existing fluid node.

• A 1D element that connects two fluid nodes.

• Surfaces of 2D arrays using triangle or quadrilateral elements.

• Volumes of 3D elements (hexahedrons, wedges, pyramids, or tetrahedrons).

You can convert any existing mesh to a microphone mesh using the Element Modify Type command and changing the element Type to the appropriate microphone element type, such as CROD - Microphone. You can convert any type of element to a microphone element.

Creating microphones using mesh primitives

You can use mesh primitives to quickly create a microphone mesh in various arrangements, such as a box, circle, or set of points. For more information, see Mesh primitives.

Acoustic power and microphone mesh size

You can use a microphone mesh to compute acoustic power, such as the total acoustic power radiated from your structure. Acoustic power is computed from the net acoustic flux on the microphone mesh using acoustic pressure and particle velocity. To ensure that large variations of pressure and particle velocity are not ignored in the computation, the microphone mesh elements must be small enough to accurately represent the acoustic response. For more information on sizing the microphone elements, see Element size for acoustic analysis

Note:

The acoustic mesh guideline of six elements per acoustic wavelength should be used if you are computing the acoustic power.

To check the frequency validity of your microphone mesh, use the Maximum Analysis Frequency scenario. For more information see: Maximum Analysis Frequency scenario (Acoustics BEM)

Microphone output results

You can request the output for microphone mesh results in the output requests for acoustic and vibro-acoustic solutions in the Simcenter Nastran FEM and Acoustics BEM solver environments.

Solver environment	Analysis Type	Microphone mesh results
Simcenter Nastran	Acoustic	Acoustic PressureParticle VelocityAcoustic IntensityAcoustic PowerPressure Modal Contributions
Vibro-Acoustic	Acoustic PressureParticle VelocityAcoustic IntensityAcoustic PowerPressure Modal ContributionsPressure Panel Contributions
Acoustics BEM		Acoustic mesh results	Microphone results
Direct Acoustic	Acoustic Pressure (Vector SORT1)Normal Velocity (Vector SORT1)Normal Intensity (Vector SORT1)	Acoustic Pressure (Vector SORT1 and Function SORT2)Velocity (Vector SORT1)Intensity (vector SORT1)Acoustic Power (radiated power) (Function SORT2)
Indirect Acoustic		Acoustic Pressure (Vector SORT1 and Function SORT2)Velocity (Vector SORT1)Intensity (Vector SORT1)Acoustic Power (radiated power) (Function SORT2)
Indirect Vibro-Acoustic		Acoustic Pressure (Vector SORT1 and Function SORT2)Velocity (Vector SORT1)Intensity (Vector SORT1)Pressure Panel Contributions (Function SORT2)Acoustic Power (radiated power) (Function SORT2)Power Panel Contributions (Function SORT2)

You can plot:

• SORT1 vector results in the Post Processing Navigator.

• SORT2 function results in the XY Function Navigator (Simcenter Nastran FEM only).

• SORT1 and SORT2 function results by creating a Post-Processing Scenario.

How do I

Request output for Direct Acoustic, Indirect Acoustic, and Indirect Vibro-Acoustic analysis types (Acoustics BEM)

Plot acoustic results for an acoustic mesh or microphone mesh (Acoustics BEM)

Learn more

Mesh primitives for acoustics and vibro-acoustics analysis

Quick links

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Using microphone mesh to capture analysis results, Simcenter 3D 2021.1 Series

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