On the frequency domain formulation of the generalized sound extrapolation method

Area of Science:

• Acoustics
• Computational Fluid Dynamics
• Aerodynamics

Background:

• Aeroacoustics problems require accurate sound prediction.
• Traditional time domain methods can be computationally intensive.
• Efficient sound extrapolation is crucial for noise analysis.

Purpose of the Study:

• To develop a frequency domain formulation for generalized sound extrapolation.
• To apply and validate the method for various aeroacoustic scenarios.
• To demonstrate the computational advantages over time domain approaches.

Main Methods:

• Fourier transform of flow variables to obtain source terms.
• Solving the inhomogeneous convected Helmholtz equation in the frequency domain using Green's functions.
• Application to 2D/3D monopoles, flat plate-gust interaction, and co-flowing jets.

Main Results:

• The frequency domain formulation shows close agreement with time domain solutions.
• Significant time savings are achieved by eliminating the need for retarded time interpolation.
• 2D computations are simplified using direct Green's function application.

Conclusions:

• The proposed frequency domain method is a viable and efficient alternative for aeroacoustic sound projection.
• This formulation offers substantial computational benefits, particularly for complex 2D and 3D problems.
• The method holds potential for broader application in aeroacoustic noise prediction and analysis.