The Effects of a Morphed Trailing-Edge Flap on the Aeroacoustic and Aerodynamic Performance of a 30P30N Aerofoil

Joseph Watkins,Abdessalem Bouferrouk

doi:10.3390/acoustics4010015

Joseph Watkins, Abdessalem Bouferrouk

Open Access

https://doi.org/10.3390/acoustics4010015

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Abstract

This paper presents initial results on the aeroacoustic and aerodynamic effects of morphing the trailing-edge flap of the 30P30N aerofoil, over five flap deflections (5–25°), at an 8° angle of attack and a Reynolds number of Re=9.2×105. The Ffowcs-Williams–Hawkings acoustic analogy estimates the far-field noise, whilst the flow field is solved using URANS with the four-equation Transition SST model. Aerodynamic and aeroacoustic simulation data for the 30P30N’s full configuration compare well with experimental results. A Courant number (C) ≤ 1 should be used for resolving tonal noise, whilst a C of up to 4 is sufficient for broadband noise. Sound pressure level results show an average 11% reduction in broadband noise across all flap deflections and frequencies for the morphed configuration compared with the conventional, single-slotted flap. The morphed flap eliminates the multiple tonal peaks observed in the conventional design. Beyond 15° flap deflection, the morphing flap achieves higher stall angles, but with increased drag, leading to a maximum reduction of 17% in Cl/Cd ratio compared with the conventional flap. The methodology reported here for the 30P30N is a quick tool for initial estimates of the far-field noise and aerodynamic performance of a morphing flap at the design stage.

Highlights

A significant proportion of this noise is a direct consequence of the deployment of high-lift devices in the form of leading-edge slats and trailing-edge flaps
Re = of 10 tunnel experiments, replicated in Ansys Fluent—with a Reynolds number Re = 1.71 × 106 (Mach (Mach number M = 0.17)—were used for pressure and aerodynamic performance validanumber M = 0.17)—were used for pressure and aerodynamic performance validation, number of of tion, whereas conditions of Reynolds number number
The preliminary results presented in this paper contribute to understanding how, at the initial design stage, morphing the trailing edge flap of a 30P30N high-lift configuration affects acoustic noise generation compared with a traditional Fowler flap design, and how this morphing affects aerodynamic performance

Summary

Introduction

Aircraft engine noise has been reduced significantly through innovations, resulting in the mass production of high-bypass-ratio turbofan engines such as the Rolls Royce Trent engine line. A significant proportion of this noise is a direct consequence of the deployment of high-lift devices in the form of leading-edge slats and trailing-edge flaps. Projects such as the work presented in this paper have increased in relevance recently because residential areas surrounding airports are becoming more densely populated. Past research has shown the damaging effects of aircraft noise near residential areas due to disturbing sleep patterns (Chen et al [1]), leading to increased stress levels, damage to surrounding ecosystems, and reduced wildlife populations. Projects such as NASA’s Quiet Aircraft Technology (QAT) project have appeared, with the aim of improving the quality of life for those most impacted by aircraft noise (Whitfield [2])

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