Leading edge serrations for the reduction of aerofoil self-noise at low angle of attack, pre-stall and post-stall conditions
Giovanni Lacagnina, Chaitanya C. Paruchuri, Junghoon Kim, Tim Berk, Phillip Joseph, Kwing-So Choi, Bharathram Ganapathisubramani, Seyed Mohammad Hasheminejad, Tze Pei Chong, Oksana Stalnov, M. F. Shahab, Mohammad Omidyeganeh, Alfredo Pinelli
Abstract
This paper addresses the usefulness of leading edge serrations for reducing aerofoil self-noise over a wide range of angles of attack. Different serration geometries are studied over a range of Reynolds number [Formula: see text]. Design guidelines are proposed that permit noise reductions over most angles of attack. It is shown that serration geometries reduces the noise but adversely effect the aerodynamic performance suggesting that a trade-off should be sought between these two considerations. The self-noise performance of leading edge serrations has been shown to fall into three angle of attack (AoA) regimes: low angles where the flow is mostly attached, moderate angles where the flow is partially to fully separated, and high angles of attack where the flow is fully separated. Leading edge serrations have been demonstrated to be effective in reducing noise at low and high angles of attack but ineffective at moderate angles. The noise reduction mechanisms are explored in each of three angle regimes.