Wake dynamics of tapered wings. Part I: a computational study

Ribeiro, Jean Helder M.; Taira, Kunihiko; Neal, Jacob; Amitay, Michael; Burtsev, Anton; Theofilis, Vassilios

doi:10.2514/6.2023-2297

Cited by 3 publications

(1 citation statement)

References 34 publications

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“…Thus far, however, most studies have not considered wing-taper effects on low-Reynolds-number flows at high angles of attack. Only recently, a combined experimental, numerical and theoretical effort has been initiated towards the understanding of the laminar flow over tapered wings in post-stall flow conditions (Burtsev et al 2023;Neal et al 2023b;Ribeiro et al 2023a). Effects of taper have been analysed for planforms with tubercles to analyse swimming of whales (Wei, New & Cui 2018), for flows over tapered cylinders (Piccirillo & Van Atta 1993;Techet, Hover & Triantafyllou 1998;Valles, Andersson & Jenssen 2002) and for separated wakes over tapered plates (Narasimhamurthy, Andersson & Pettersen 2008).…”

Section: Introductionmentioning

confidence: 99%

Laminar post-stall wakes of tapered swept wings

Ribeiro,

Neal,

Burtsev

et al. 2023

J. Fluid Mech.

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While tapered swept wings are widely used, the influence of taper on their post-stall wake characteristics remains largely unexplored. To address this issue, we conduct an extensive study using direct numerical simulations to characterize the wing taper and sweep effects on laminar separated wakes. We analyse flows behind NACA 0015 cross-sectional profile wings at post-stall angles of attack $\alpha =14^\circ$ – $22^\circ$ with taper ratios $\lambda =0.27$ – $1$ , leading-edge sweep angles $0^\circ$ – $50^\circ$ and semi aspect ratios $sAR =1$ and $2$ at a mean-chord-based Reynolds number of $600$ . Tapered wings have smaller tip chord length, which generates a weaker tip vortex, and attenuates inboard downwash. This results in the development of unsteadiness over a large portion of the wingspan at high angles of attack. For tapered wings with backward-swept leading edges, unsteadiness emerges near the wing tip. On the other hand, wings with forward-swept trailing edges are shown to concentrate wake-shedding structures near the wing root. For highly swept untapered wings, the wake is steady, while unsteady shedding vortices appear near the tip for tapered wings with high leading-edge sweep angles. For such wings, larger wake oscillations emerge near the root as the taper ratio decreases. While the combination of taper and sweep increases flow unsteadiness, we find that tapered swept wings have more enhanced aerodynamic performance than untapered and unswept wings, exhibiting higher time-averaged lift and lift-to-drag ratio. The current findings shed light on the fundamental aspects of flow separation over tapered wings in the absence of turbulent flow effects.

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