33.3.31 Acoustics Model Dialog Box

The Acoustics Models dialog box allows you to set parameters related to the acoustics model. See Section  22.2 for details about the items below.

Controls

Model   contains the option for turning on the acoustics model.

Off   disables the acoustics model.

Ffowcs-Williams & Hawkings   enables the Ffowcs Williams and Hawkings (FW-H) acoustics model. See Section  22.2.5 for details.

Broadband Noise Sources   enables the broadband noise acoustics model. See Section  22.3 for details.

Model Constants   contains parameters related to the acoustics model.

Far-Field Density   sets the value of the far-field fluid density ( $\rho_0$ in this equation in the separate Theory Guide).

Far-Field Sound Speed   sets the speed of the sound at the far-field ( $a_0$ in this equation and this equation in the separate Theory Guide).

Reference Acoustic Pressure   is used to calculate the sound pressure level in dB.

Reference Acoustic Power   is used to non-dimensionalize the acoustic power, giving the sound pressure level in dB (see Section  29.11). This parameter is equal to $4 \times 10^{-10}$ W for airborne sound and $10^{-12}$ W for underwater sound.

Reference Acoustic Intensity   is defined as $p_{\rm ref}^2/(\rho_0 a_0)$, although this quantity is not currently used by ANSYS FLUENT.

Source Correlation Length   is required when sound is to be computed using a 2D flow result. The FW-H integrals will be evaluated over this length in the depthwise direction using the identical source data.

Number of Realizations   is the number of times the noise source terms will be computed through the generation of stochastic turbulent velocity field.

Number of Fourier Modes   is the number of terms in the Fourier summation from which the turbulent velocity field and its derivatives are computed.

Number of Time Steps Per Revolution   is available only for steady-state cases that have a single rotating reference frame. Here you will specify the number of equivalent time steps that it will take for the rotating zone to complete one revolution.

Number of Revolutions   is available only for steady-state cases that have a single rotating reference frame. Here you will specify the number of revolutions that will be simulated in the model.

Options   contains the parameters related to Ffowcs-Williams & Hawkings model.

Export Acoustic Source Data in ASD Format   enables/disables the saving of source data files in ASD format.

Export Acoustic Source Data in CGNS Format   enables/disables the saving of source data files in CGNS format.

Compute Acoustics Signals Simultaneously   enables "on-the-fly'' calculation of sound. When this option is chosen, the ANSYS FLUENT console window will print a message at the end of each time step indicating that the sound pressure signals have been computed (e.g., Extracting sound signals at x receiver locations ..., where x is the number of receivers you specified). Enabling this option instructs ANSYS FLUENT to compute sound pressure signals at the end of each time step, which will slightly increase the computation time.

Define Sources...   opens the Acoustic Sources dialog box, which allows you to specify the acoustics sources.

Define Receivers...   opens the Acoustic Receivers dialog box, which allows you to specify the location of the receivers.

Apply   saves the acoustics model settings.