Triglobal resolvent analysis of swept-wing wakes

Ribeiro, Jean Helder M.; Yeh, C.; Taira, Kunihiko

doi:10.1017/jfm.2022.1033

Cited by 10 publications

(10 citation statements)

References 67 publications

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“…2020 a ; Ribeiro et al. 2023 b ). For highly swept and tapered wings, the flow exhibits wake shedding for small , as shown in figure 10( a ).…”

Section: Resultsmentioning

confidence: 99%

“…2020 a ; Ribeiro et al. 2022, 2023 b ), is further noticed in both experiments and high-fidelity large-eddy simulations performed at a higher-Reynolds-number regime (Harper & Maki 1964; Visbal & Garmann 2019).…”

Section: Introductionmentioning

confidence: 83%

“…For instance, for low-Reynolds-number flows over swept wings, some of the core coherent structures emerging in the near wake, such as the 'ram's horn' vortex and the canard leading-edge vortices, were also identified in experiments performed at higher Reynolds numbers (Black 1956;Breitsamter & Laschka 2001;Neal et al 2023a). Moreover, the stabilizing effect of the sweep-induced spanwise flow on the wake structures, which significantly impacts stall characteristics, as observed at low-Reynolds-number flows (Zhang et al 2020a;Ribeiro et al 2022Ribeiro et al , 2023b, is further noticed in both experiments and high-fidelity large-eddy simulations performed at a higher-Reynolds-number regime (Harper & Maki 1964;Visbal & Garmann 2019).…”

Section: Introductionmentioning

confidence: 94%

“…2020 a ) and identify global modes (Burtsev et al. 2022; Ribeiro, Yeh & Taira 2023 b ) that give rise to fundamental global coherent structures of flow separation around swept wings. It is noteworthy that some of the wing-sweep effects on laminar post-stall flows are topologically analogous over a wide range of Reynolds numbers.…”

Section: Introductionmentioning

confidence: 99%

“…Wing sweep also has a strong influence on post-stall wake dynamics. For laminar flow regimes, a number of experimental and numerical efforts were made to examine the effects of backward and forward wing sweep (Yen & Hsu 2007;Yen & Huang 2009;Zhang et al 2020a) and identify global modes (Burtsev et al 2022;Ribeiro, Yeh & Taira 2023b) that give rise to fundamental global coherent structures of flow separation around swept wings. It is noteworthy that some of the wing-sweep effects on laminar post-stall flows are topologically analogous over a wide range of Reynolds numbers.…”

Section: Introductionmentioning

confidence: 99%

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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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“…2020 a ; Ribeiro et al. 2023 b ). For highly swept and tapered wings, the flow exhibits wake shedding for small , as shown in figure 10( a ).…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Laminar post-stall wakes of tapered swept wings

Ribeiro,

Neal,

Burtsev

et al. 2023

J. Fluid Mech.

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An invitation to resolvent analysis

Rolandi,

Ribeiro,

Yeh

et al. 2024

Theor. Comput. Fluid Dyn.

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Resolvent analysis is a powerful tool that can reveal the linear amplification mechanisms between the forcing inputs and the response outputs about a base flow. These mechanisms can be revealed in terms of a pair of forcing and response modes and the associated energy gains (amplification magnitude) at a given frequency. The linear relationship that ties the forcing and the response is represented through the resolvent operator (transfer function), which is constructed through spatially discretizing the linearized Navier–Stokes operator. One of the unique strengths of resolvent analysis is its ability to analyze statistically stationary turbulent flows. In light of the increasing interest in using resolvent analysis to study a variety of flows, we offer this guide in hopes of removing the hurdle for students and researchers to initiate the development of a resolvent analysis code and its applications to their problems of interest. To achieve this goal, we discuss various aspects of resolvent analysis and its role in identifying dominant flow structures about the base flow. The discussion in this paper revolves around the compressible Navier–Stokes equations in the most general manner. We cover essential considerations ranging from selecting the base flow and appropriate energy norms to the intricacies of constructing the linear operator and performing eigenvalue and singular value decompositions. Throughout the paper, we offer details and know-how that may not be available to readers in a collective manner elsewhere. Towards the end of this paper, examples are offered to demonstrate the practical applicability of resolvent analysis, aiming to guide readers through its implementation and inspire further extensions. We invite readers to consider resolvent analysis as a companion for their research endeavors.

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Progress in physical modeling of compressible wall-bounded turbulent flows

Cheng,

Chen,

Zhu

et al. 2024

Acta Mech. Sin.

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Understanding, modeling and control of the high-speed wall-bounded transition and turbulence not only receive wide academic interests but also are vitally important for high-speed vehicle design and energy saving because transition and turbulence can induce significant surface drag and heat transfer. The high-speed flows share some fundamental similarities with the incompressible counterparts according to Morkovin’s hypothesis, but there are also significant distinctions resulting from multi-physics coupling with thermodynamics, shocks, high-enthalpy effects, and so on. In this paper, the recent advancements on the physics and modeling of high-speed wall-bounded transitional and turbulent flows are reviewed; most parts are covered by turbulence studies. For integrity of the physical process, we first briefly review the high-speed flow transition, with the main focus on aerodynamic heating mechanisms and passive control strategies for transition delay. Afterward, we summarize recent encouraging findings on turbulent mean flow scaling laws for streamwise velocity and temperature, based on which a series of unique wall models are constructed to improve the simulation accuracy. As one of the foundations for turbulence modeling, the research survey on turbulent structures is also included, with particular focus on the scaling and modeling of energy-containing motions in the logarithmic region of boundary layers. Besides, we review a variety of linear models for predicting wall-bounded turbulence, which have achieved a great success over the last two decades, though turbulence is generally believed to be highly nonlinear. In the end, we conclude the review and outline future works.

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Triglobal resolvent analysis of swept-wing wakes

Cited by 10 publications

References 67 publications

Laminar post-stall wakes of tapered swept wings

Laminar post-stall wakes of tapered swept wings

An invitation to resolvent analysis

Progress in physical modeling of compressible wall-bounded turbulent flows

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