Please use this identifier to cite or link to this item: https://hdl.handle.net/10356/143072
Title: Leading-edge tubercles delay flow separation for a tapered swept-back wing at very low Reynolds number
Authors: Wei, Zhaoyu
New, Tze How
Lian, Lian
Zhang, Yanni
Keywords: Engineering::Mechanical engineering
Issue Date: 2019
Source: Wei, Z., New, T. H., Lian, L., & Zhang, Y. (2019). Leading-edge tubercles delay flow separation for a tapered swept-back wing at very low Reynolds number. Ocean Engineering, 181, 173-184. doi:10.1016/j.oceaneng.2019.04.018
Journal: Ocean Engineering
Abstract: Flow separation characteristics for two tapered swept-back wings, one with straight leading-edge (LE) and the other with tubercled LE, were investigated in a water tunnel using time-resolved particle image velocimetry (TR-PIV) technique. The two wings were based on the SD7032 aerofoil profile, with Reynolds number Re = 1.4 × 104, close to the working condition for common underwater gliders. The LE tubercles were designed such that the amplitude decreased linearly from the wing root to wing tip, while retaining constant wavelength. Results indicate that the baseline wing shows significantly separated flow in the outboard region at pitch angle of 10° and 20°, and the flow remains attached in the inboard region due to relatively larger local Reynolds number. Implementation of LE tubercles can mitigate flow separation downstream of both troughs and peaks. At higher pitch angles, the separated flows cover most of the baseline wing surface, whereas flow remains attached downstream most of tubercle peaks. Streamwise aligned counter-rotating vortex pairs (CVPs) formed over the tubercles are significantly tilted and asymmetrical due to the sweep and amplitude difference between the two sides of tubercle. Consequently, weaker vortices in CVPs close to the wing root are rapidly dissipated, allowing the CVPs to evolve into a series of co-rotating vortices (CVs), which exerted significant impact on flow separation characteristics downstream of the tubercles.
URI: https://hdl.handle.net/10356/143072
ISSN: 0029-8018
DOI: 10.1016/j.oceaneng.2019.04.018
Rights: © 2019 Elsevier Ltd. All rights reserved. This paper was published in Ocean Engineering and is made available with permission of Elsevier Ltd.
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:MAE Journal Articles

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