LEE Sources Model Reference

The LEE Sources model uses Linearized Euler Equations (LEE) to compute the turbulent shear flow noise of quadropole sources from a synthetic turbulent velocity field.

Note	This model only solves for noise sources—not for acoustic wave propagation.

Table 1. LEE Sources Model Reference
Theory	See Linearized Euler Equation (LEE) Noise Source Model.
Provided By	[physics continuum] > Models > Broadband Noise Source Models
Example Node Path	Continua > Physics 1 > Models > LEE Sources
Requires	Space: Two Dimensional, Three Dimensional, or Axisymmetric Time: Steady Material: any but solid Flow: any Viscous Regime: Turbulent Turbulence: Reynolds-Averaged Navier-Stokes Reynolds-Averaged Turbulence: any Optional Models: Aeroacoustics Aeroacoustics Models: Broadband Noise Sources
Properties	Key properties are: Number of Realizations Number of Fourier Modes See LEE Sources Model Properties.
Activates	Solvers	LEE Source Solver See LEE Source Solver.
	Field Functions	LEE Self Noise Source LEE Shear Noise Source LEE Total Noise Source See Field Functions.

LEE Sources Model Properties

Number of Realizations: The number of samples used to compute the average of the synthetic turbulent velocity field based on the Stochastic Noise Generation and Radiation (SNGR) approach.; The default value is 200. You can use up to 1000 realizations (see Karweit et al. [66]).; Increasing the number of realizations increases accuracy but also computational costs.
Number of Fourier Modes: The number of the Fourier modes $n$ used for the spectral resolution for isotropic turbulence given by a von Karman-Pao spectrum, when computing the synthetic turbulent velocity field, see Eqn. (4698)).; The default value is 50. Use values between 30 and 50 Fourier modes.; Increasing the number of Fourier modes increases accuracy but also computational costs.

LEE Source Solver

The LEE Source solver controls the iterative update for the noise source calculations. First, the LEE Source solver calls the Stochastic Noise Generation and Radiation (SNGR) solver, then computes the LEE noise source terms. The SNGR solver computes the synthetic turbulent velocity field and gradients of that field using the SNGR method.

The following right-click action is available:

Execute solver: Calculates the values for the LEE Sources field functions. To stop the solver immediately, without completing the set number of realization steps, click on the solver stop button located next to the progress bar. The solver stops and saves the partially computed field functions.

Field Functions

LEE Self Noise Source: The LEE source term that computes the sound generated by turbulent velocity components, see $S_{S e l f N o i s e T e r m}$ given by Eqn. (4696).
LEE Shear Noise Source: The LEE source term that computes the acoustic effects from the interaction between the mean shear flow and turbulent velocity components, see $S_{S h e a r N o i s e T e r m}$ given by Eqn. (4692).
LEE Total Noise Source: The sum of the LEE Self Noise Source and LEE Shear Noise Source.