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Item Experimental Study on the Effect of Tubercle on Aerodynamic Characteristics of Swept Wings at low Reynolds Number(Springer Science and Business Media Deutschland GmbH, 2022) Joseph, J.; Sathyabhama, A.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.Item Experimental and numerical analysis of humpback whale inspired tubercles on swept wings(Emerald Publishing, 2022) Joseph, J.; A, S.; Sridhar, S.Purpose: With aims to increase the aerodynamic efficiency of aerodynamic surfaces, study on flow control over these surfaces has gained importance. With the addition of flow control devices such as synthetic jets and vortex generators, the flow characteristics can be modified over the surface and, at the same time, enhance the performance of the body. One such flow control device is the tubercle. Inspired by the humpback whale’s flippers, these leading-edge serrations have improved the aerodynamic efficiency and the lift characteristics of airfoils and wings. This paper aims to discusses in detail the flow physics associated with tubercles and their effect on swept wings. Design/methodology/approach: This study involves a series of experimental and numerical analyses that have been performed on four different wing configurations, with four different sweep angles corresponding to 0°, 10°, 20° and 30° at a low Reynolds number corresponding to Rec=100,000. Findings: Results indicate that the effect of tubercles diminishes with an increase in wing sweep. A significant performance enhancement was observed in the stall and post-stall regions. The addition of tubercles led to a smooth post-stall lift characteristic compared to the sudden loss in the lift with regular wings. Among the four different wings under observation, it was found that tubercles were most effective on the 0° configuration (no sweep), showing a 10.8% increment in maximum lift and a 38.5% increase in the average lift generated in the post-stall region. Tubercles were least effective on 30° configuration. Furthermore, with an increase in wing sweep, co-rotating vortices were distinctly observed rather than counter-rotating vortices. Originality/value: While extensive numerical and experimental studies have been performed on straight wings with tubercles, studies on the tubercle effect on swept wings at low Reynolds number are minimal and mainly experimental in nature. This study uses numerical methods to explore the complex flow physics associated with tubercles and their implementation on swept wings. This study can be used as an introductory study to implement passive flow control devices in the low Reynolds number regime. © 2022, Emerald Publishing Limited.