Department of Mechanical and Aerospace EngineeringNEWS & EVENTS
MPhil THESIS PRESENTATION

Aerodynamic and Acoustic Performance of an Airfoil with Leading Edge Serrations

Ms Shengyang GAO
Department of Mechanical and Aerospace Engineering, HKUST
Date  :  31 May 2017 (Wed)
Time  :  10:00 a.m.
Venue  :  Room 5560, HKUST (5/F., Lift #27/28)

Abstract

This thesis provides a detailed account of an experimental investigation into the aerodynamic and acoustic effects of leading edge (LE) serrations on an artificial airfoil NACA0012. The geometry of the leading edge serrations in this thesis was inspired by the morphology of the owl’s wings LE serrations. This thesis aims at investigating the influences on airfoil’s lift, drag and noise performance brought by the LE serrations, and the specific geometrical parameters of the serrations that may affect the airfoil’s performance.

The presence of LE serrations degrades the aerodynamic efficiency L/D of the airfoil in the pre-stall region, due to the decrease of maximum lift and an early increase of drag. However, the ability of retaining lift and reducing drag in the post-stall region enables the airfoil with LE serrations to maintain a slower pace for the decreasing L/D. Serrations with a smaller height and larger wavelength tend to produce higher lift and lower drag comparing to other serrations.

Effects of LE serration on the airfoil self-noise are two-sided. The presence of LE serrations are beneficial in regard of reducing/eliminating airfoil’s tonal noise, while in the case of broadband noise at higher angles of attack (above 6°), LE serrations are usually detrimental by significantly increasing the SPL at medium to high frequencies. Height is found to be essential to the serrations’ influences on both tonal noise and broadband noise: larger height is beneficial to tones reduction/elimination, but it also causes higher broadband noise at frequencies above 1.5kHz.

(Co-supervisors: Prof. Xin ZHANG and Prof. Larry LI)