Broadband trailing edge noise from a sharp-edged strut.

Area of Science:

• Fluid Dynamics
• Aeroacoustics
• Aerodynamics

Background:

• Trailing edge noise is a significant factor in aerodynamic applications.
• Existing semi-empirical models often fail to accurately predict noise spectra, particularly at lower frequencies.
• Understanding flow structures in the near wake is crucial for noise prediction.

Purpose of the Study:

• To present experimental data on flow and noise from sharp-edged flat plates.
• To evaluate the accuracy of existing semi-empirical trailing edge noise prediction methods.
• To develop an improved semi-empirical model for predicting trailing edge noise.

Main Methods:

• Experimental measurements of flow and noise generated by a sharp-edged flat plate.
• Analysis of velocity spectra in the near wake region.
• Evaluation of multiple semi-empirical trailing edge noise prediction models.
• Derivation of a new semi-empirical model for surface pressure spectrum.

Main Results:

• Experimental data were collected for Reynolds numbers ranging from 2.0 × 10^5 to 5.0 × 10^5.
• All evaluated semi-empirical methods under-predicted noise at lower frequencies.
• Energetic velocity fluctuations were observed at low frequencies in the near wake.
• A new semi-empirical model for the surface pressure spectrum was derived.

Conclusions:

• Current semi-empirical models are inadequate for predicting trailing edge noise at low-to-moderate Reynolds numbers.
• Low-frequency velocity fluctuations in the near wake are a key factor influencing noise generation.
• The derived semi-empirical model offers a potential improvement for trailing edge noise prediction.