On the efficient modeling of generic source directivity in Gaussian beam tracing

Area of Science:

• Acoustics
• Computational Physics
• Wave Propagation

Background:

• Gaussian beam tracing (GBT) is used for large-distance sound propagation but typically employs omnidirectional sources, ignoring real-world directivity.
• Previous methods to model source directivity using multiple point sources are computationally expensive and complex.
• Accurate modeling of source directivity is crucial for realistic acoustic simulations.

Purpose of the Study:

• To develop an efficient and accurate method for incorporating generic source directivity into GBT.
• To reduce the computational cost associated with modeling complex acoustic sources.

Main Methods:

• A complex-valued radiation function model was developed for GBT.
• This model allows a single source to emit rays with direction-dependent amplitude and phase.
• The radiation function is integrated with the GBT method for sound field computation.

Main Results:

• The new method shows good agreement with analytical and wave-based numerical solutions in verification cases.
• It successfully modeled a spinning sound field to mimic propeller noise, matching analytical results.
• A demonstration case involving a four-propeller drone in an urban environment was successfully conducted.

Conclusions:

• The complex-valued radiation function provides an efficient and accurate way to implement generic source directivity in GBT.
• This approach significantly reduces computational cost compared to multi-source methods.
• The method is effective for complex acoustic modeling, including phenomena like propeller noise.