Downstream perforations for the reduction of turbulence-aerofoil interaction noise: Part II - theoretical investigation

Priddin, Matthew, Ayton, Lorna, Palleja Cabre, Sergi, Paruchuri, Chaitanya and Joseph, Phillip (2021) Downstream perforations for the reduction of turbulence-aerofoil interaction noise: Part II - theoretical investigation. In AIAA AVIATION 2021 FORUM. (doi:10.2514/6.2021-2147).

Abstract

This paper presents a theoretical study of introducing a single gap or slot downstream of the leading edge of a thin rigid plate on aeroacoustic scattering. This is investigated as an elementary model for understanding the effect of downstream perforations on gust-aerofoil interaction noise. Across the slot it is supposed there is zero pressure jump, and a wake is shed from the upstream slot edge such that an unsteady Kutta condition is satisfied. The resulting mixed boundary value problem is reformulated as a Wiener–Hopf problem, and reduced to asingular integral equation suitable for numerical solution. Wave components of the solution may be identified, and plausibly related to diffracted fields by each junction. Theoretical results are compared to experimental results considering sets of perforations. The model is found to be in line with overall qualitative trends in the change in far-field sound power level observed experimentally, but does not account for oscillations from this trend.

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Contributors

Author: Sergi Palleja Cabre

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