22.3.1 Enabling the Broadband Noise Source Models

To enable the broadband noise sources models, select Broadband Noise Sources in the Acoustics Model dialog box (Figure  22.3.1).

Models Acoustics Edit...

Figure 22.3.1: The Acoustics Model Dialog Box for Broadband Noise

Setting Model Constants

Under Model Constants in the Acoustics Model dialog box, specify the relevant acoustic parameters and constants used by the model. See Section  22.2.1 for the definitions of Far-Field Density and Far-Field Sound Speed.

Reference Acoustic Power   (for example, $P_{\rm ref}$ in this equation in the separate Theory Guide) is used to compute the acoustic power outputs in decibels (dB). The default value is $10^{-12}$. Note that the units for the reference acoustic power will be different in 2D ( $W/m^2$) and 3D ( $W/m^3$) cases.

Number of Realizations   is the number of samples used in the SNGR to compute the averaged source terms of LEE and Lilley's equations. The default value is 200.

Number of Fourier Modes   ( $N$ in this equation in the separate Theory Guide) is the number of the Fourier modes used to compute the turbulent velocity field and its derivatives. The turbulent velocity field is then used to compute the LEE and Lilley's source terms. The default value is 50.