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Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow
Published on: February 27, 2016
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Resolvent-based modeling of turbulent jet noise
Ethan Pickering1, Aaron Towne2, Peter Jordan3
1Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California 91125, USA.
The Journal of the Acoustical Society of America
|October 31, 2021
Summary
Resolvent analysis models jet acoustics by relating near-field forcing to pressure fields. A single resolvent mode accurately reconstructs energetic acoustic regions, enabling a rank-1 model for jet noise prediction.
Area of Science:
- Fluid dynamics
- Aeroacoustics
- Computational physics
Background:
- Resolvent analysis shows promise in modeling coherent structures in jets.
- Large-eddy simulations (LES) provide high-fidelity data for comparison.
- Acoustic analogies can link near-field forcing to far-field pressure.
Purpose of the Study:
- Formulate resolvent analysis as an acoustic analogy.
- Relate near-field resolvent forcing to jet acoustic fields.
- Develop a low-rank model for jet noise prediction.
Main Methods:
- Utilized an LES database of round, isothermal jets (Mach 0.9 and 1.5).
- Projected acoustic fields onto a limited set of resolvent modes.
- Employed near-field (r/D=[5,6]) and far-field (Kirchhoff surface) projections.
- Derived a low-rank, cross-spectral density matrix.
Main Results:
- A single resolvent mode reconstructed the most energetic acoustic field regions.
- This was observed across Strouhal numbers St=[0-1] and azimuthal wavenumbers m=[0,2].
- A simple function yielded a rank-1 resolvent model within 2 dB of peak noise.
Conclusions:
- Resolvent analysis, framed as an acoustic analogy, effectively models jet acoustics.
- Low-rank resolvent models can accurately predict jet noise.
- This approach offers a computationally efficient method for aeroacoustic predictions.
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