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A semi-analytical method for two-dimensional sound propagation in subsonic parallel mean flow
Jinxiao Li1, Haijun Wu1, Changjiang Liao2
1State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China.
The Journal of the Acoustical Society of America
|September 5, 2025
Summary
A new method, the linear-velocity-profile fast field program (LFFP), accurately predicts 2D sound fields in flows. It improves precision and efficiency, especially with high velocity gradients, outperforming traditional methods.
Area of Science:
- Acoustics
- Fluid Dynamics
- Computational Physics
Background:
- Predicting sound propagation in moving fluids is crucial for applications like noise control and sonar.
- Traditional Fast Field Program (FFP) methods face challenges with high velocity gradients in ambient flows.
- Accurate modeling of sound fields in complex flow environments remains an active research area.
Purpose of the Study:
- To introduce a novel semi-analytical method, the linear-velocity-profile fast field program (LFFP), for enhanced prediction of 2D sound fields.
- To improve computational efficiency and accuracy of sound field predictions in parallel mean flows, particularly those with significant velocity gradients.
- To provide a systematic mathematical explanation for the improved accuracy of LFFP compared to traditional FFP.
Main Methods:
- Developed the linear-velocity-profile fast field program (LFFP) by integrating linear velocity layering into the Fast Field Program (FFP) framework.
- Validated LFFP accuracy using a 2D jet case against the linearized Euler equation in the frequency domain.
- Employed residual analysis to investigate and explain the enhanced precision of LFFP in shear flow scenarios.
Main Results:
- LFFP demonstrates superior accuracy and reduced computational cost compared to traditional FFP, especially in high-velocity gradient conditions.
- Validation against the linearized Euler equation confirms the predictive capabilities of LFFP for 2D sound fields.
- Identified the consideration of the second velocity gradient term in the Pridmore-Brown operator as key to LFFP's improved precision.
Conclusions:
- The LFFP method offers a significant advancement in predicting 2D sound fields in parallel mean flows.
- The developed multi-staircase layering model, based on residual analysis, further enhances computational efficiency for complex ambient environments.
- LFFP provides a more accurate and efficient tool for acoustic modeling in dynamic fluid environments.
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