Experimental Study on the Effect of Tubercle on Aerodynamic Characteristics of Swept Wings at low Reynolds Number

Abstract

Inspired from the Humpback whale flipper, airfoils and wings incorporated with sinusoidal leading edge are much studied for their improved aerodynamic characteristics like delayed stall and higher lift in post-stall region. In this work, the performance of different swept wings equipped with leading edge tubercles is studied by comparing with their baseline models at a low Reynolds number of 100,000. Tubercles on swept wings can either be placed normal to leading edge or parallel to flow direction. First part of the study involves selecting the swept wing configuration which has superior aerodynamic performance from the two possible configurations based on the tubercle alignment on it. Wind tunnel experiment is conducted for the above-mentioned configuration of tubercles on different swept wings as well as unswept wing and compared to corresponding baseline wings. The orientation of tubercle relative to flow has a significance in aerodynamic performance. Aerodynamic efficiency is maximum when the tubercles are aligned with the flow direction. It is seen that tubercles on high swept wing are not as effective as it is on a unswept wing. On unswept and low swept, wing tubercles improve the stall characteristics by preventing abrupt stall and maintaining high lift in post-stall regime. The lift-to-drag ratio for these wings is improved when tubercles are introduced. However, for high swept, wing tubercles do not change the aerodynamic characteristics significantly. © 2021, Shiraz University.