Prediction of Trailing-Edge Noise for Separated Turbulent Boundary Layers

Abstract

This paper presents a semi-empirical low-order prediction of the trailing-edge noise of separated turbulent boundary layers. The prediction focuses on obtaining the low-frequency spectral peak of the far-field sound pressure level by modeling the measured wavenumberfrequency spectrum using regression analysis and integrating that spectrum in the manner of Howe's radiation model. Surface pressure fluctuations upstream of the trailing-edge of a DU96-W-180 blade section were measured using miniature pressure transducers, and the trailingedge noise was measured using a directional microphone. The prediction showed that the far-field sound pressure level reached its maximum below the frequency limit of the directional microphone measurement, between 400 Hz-500 Hz depending on the freestream velocity and the predicted spectrum varied between ±0.5 dB given the inaccuracies of the regression model.