Monopole Point Source

Use the node to add a monopole point source in 3D components on any point and in 2D axisymmetric components on points on the axis of symmetry. This is a source that is uniform and equally strong in all directions. A monopole represents a radially pulsating sphere in the limit where the radius tends to zero. The monopole point source adds a point source term to the right-hand side of the governing Helmholtz equation such that:

where

is the delta function in three dimensions and adds the source at the point where x = x0. The monopole amplitude S (SI unit: N/m2) depends on the source type selected, as discussed below.


	For the Pressure Acoustics, Transient interface, only the Flow (no phase specification), User defined, and the Gaussian pulse source types are available. The Gaussian pulse source type has no effect in the frequency domain. See The Gaussian Pulse Source Type Settings.

Select a : (the default), , , or .

For enter a , S = Suser (SI unit: N/m).

Flow

Select to add an monopole point source located at x = x0 defined in terms of the volume flow rate out from source QS and the phase

of the source. The source defines the following monopole amplitude:

Enter values or expressions for:

•

, QS (SI unit: m3/s).

•

(SI unit: rad).

Intensity

Select to define the source in terms of the free space reference RMS intensity Irms it radiates. In a homogeneous medium, the specified intensity is obtained (the reference), but with other objects and boundaries present the actual intensity is different. The source defines the following monopole amplitude:

where dsrc is the distance from the source where the intensity Irms is specified and

is the phase of the source. Enter values or expressions for:

•

, Irms (SI unit: W/m2).

•

dsrc (SI unit: m).

•

(SI unit: rad).

Power

When is selected, specify the source’s reference RMS strength by stating the power it radiates. In a homogeneous medium, the specified power is obtained (the reference), but with other objects and boundaries present the actual power is different. The source defines the following monopole amplitude:

where Pref denotes the radiated RMS power per unit length measured in W/m. Enter values or expressions for:

•

, Prms (SI unit: W).

•

(SI unit: rad).


	Bessel Panel: Application Library path Acoustics_Module/Tutorials,_Pressure_Acoustics/bessel_panel Hollow Cylinder: Application Library path Acoustics_Module/Vibrations_and_FSI/hollow_cylinder


	Point sources in 2D components also exist. They actually correspond to infinite out-of-plane line sources, see Point Sources (for 2D Components).