Sound generated in the vicinity of the trailing edge of an upper surface blown flap

Far field noise data indicated that for practical upper surface blown flap configurations, the noise radiated below the flap is dominated by the noise generated in the vicinity of the trailing edge. The sound field caused by turbulent mixing in the trailing edge wake is investigated experimentally and theoretically. Hot wire measurements were made downstream of the trailing edge to determine the gross turbulent mixing characteristics of the flow. This information is used as input to a theoretical analysis of the sound field. Favorable agreement is found between predicted and measured far field noise directivity at various frequencies and noise power spectra in various directions.