Defining acoustic sources and loads (Acoustics BEM)

You can define acoustic sources and acoustic loads in the Simcenter 3D Acoustics BEM solver environment.

Acoustic monopole source

An acoustic monopole is a pulsating sound source that radiates equally in all directions.

Acoustic monopole source

In Acoustics BEM, you can create acoustic monopoles at any location, with some restrictions:

• If the distance from the monopole to the 2D boundary mesh is less than the closest element size, the software may not accurately compute local acoustic scattering. Therefore, we recommend that you locate the monopole no closer than one element length from the 2D boundary mesh.

• If you require the monopole to be very close to the mesh, local mesh refinement may be required for an accurate solution of nearby acoustic scattering.

The incident pressure at a location of a distance R due to an acoustic monopole source is given by:

where:

p = Incident pressure (N/m2)

A = Amplitude of the source (N/m)

R = Distance from the source

k = Wave number

You can define the monopole amplitude as:

• A constant

• A complex excitation with real and imaginary parts

• A complex excitation defined by magnitude and phase angle

• A complex field that is frequency dependent

Acoustic loads

You can apply enforced acoustic pressure or normal acoustic velocity to the acoustic fluid elements with the Enforced Acoustic Pressure or the Normal Acoustic Velocity boundary conditions respectively.

You can define the magnitude of pressure or velocity as:

• A constant

• A complex excitation with real and imaginary parts

• A complex excitation defined by magnitude and phase angle

• A complex field that is frequency dependent

Where do I find it?

Creating an acoustic monopole source

Application	Pre/Post
Prerequisites	A Simulation file as the work part and displayed partSimcenter 3D Acoustics BEM as the specified solverDirect Acoustic or Indirect Acoustic or Indirect Vibro-Acoustic as the specified analysis type
Command Finder	Acoustic Monopole Source
Simulation Navigator	Expand the Solution Step node of an active solution → right-click the Loads container → New Load → Acoustic Monopole Source

Creating an enforced acoustic pressure load

Application	Pre/Post
Prerequisites	A Simulation file as the work part and displayed partSimcenter 3D Acoustics BEM as the specified solverDirect Acoustic or Indirect Acoustic or Indirect Vibro-Acoustic as the specified analysis type
Command Finder	Enforced Acoustic Pressure
Simulation Navigator	Expand the Solution Step of an active solution → right-click the Loads container → New Load → Enforced Acoustic Pressure

Creating a normal acoustic velocity load

Application	Pre/Post
Prerequisites	A Simulation file as the work part and displayed partSimcenter 3D Acoustics BEM as the specified solverDirect Acoustic or Indirect Acoustic or Indirect Vibro-Acoustic as the specified analysis type
Command Finder	Normal Acoustic Velocity
Simulation Navigator	Expand the Solution Step node of an active solution → right-click the Loads container → New Load → Normal Acoustic Velocity

How do I

Define forcing frequencies (Acoustics BEM)

Learn more

Boundary conditions (Acoustics BEM)

Assigning frequencies from all loads to subcases

Distributed Acoustic Plane Waves loading for indirect acoustic and vibro-acoustic analyses (Acoustics BEM)

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Defining acoustic sources and loads (Acoustics BEM), Simcenter 3D 2021.1 Series

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