Predictions of Slat Noise from the 30P30N at High Angles of Attack using Zonal Hybrid RANS-LES

Over the last several decades, propulsion related aircraft noise has decreased, in part from high bypass ratio turbofan engines and nozzle geometry modifications to increase jet shear-layer mixing, as well as improved propulsion/airframe integration. These advancements have increased the relative contribution of airframe noise to the total aircraft noise footprint. The leading-edge slat deployed as part of the high-lift device is one of the major contributors to airframe noise. Broadband noise, generated from the slat leading edge shear layer and its impingement on the lower surface of the slat upstream of the trailing edge, is the primary noise source.2 At lower angles of attack, narrow band peaks are observed within the broadband which are caused by a feedback mechanism similar to Rossiter modes observed in cavities.3 An additional peak associated with slat trailing edge noise is also observed at higher frequencies correlated to the finitethickness trailing edge.4 In an e↵ort to increase the understanding of slat noise generation mechanisms and to mature the prediction capability of high-fidelity numerical simulations, the American Institute of Aeronautics and Astronautics (AIAA) has held a series of workshops for Benchmark problems for Airframe Noise Computations (BANC), which includes Category 7 Slat Noise.5 Category 7 investigates the slat noise generated by the 30P30N two-dimensional high-lift model. This configuration has been studied both experimentally6–9 and computationally.10–13 In previous workshops, BANC-II to BANC-IV, only a relatively low angle of attack case, ↵ = 5.5 degrees, was investigated. In BANC-V, two additional angles of attack, ↵ = 9.5 and 14.0 degrees were added to the problem description, in part due to the high quality acoustic data recently obtained in the 2m ⇥ 2m Kevlar-wall wind tunnel at the Japan Aerospace Exploration Agency (JAXA).1 The authors have been consistent contributors to the workshop since BANC-III, and the Category 7 Slat Noise case has been a driving stimulus to several modeling and simulation enhancements within the Launch Ascent and Vehicle Aerodynamics (LAVA) solver framework.14 In addition to the BANC workshop contributions on slat noise, an installed version of the 30P30N with a retracted flap which was studied experimentally in the