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• W2997502877 abstract "•Hummingbirds counter a challenging, continuous perturbation in their first attempt•Roll control uses bilaterally different muscle activation, posture, and tail fanning•Differential wing rotation and elevation generate oval versus figure 8 tip trajectories•Computational simulations show wing rotation to be critical to mitigate perturbation Both biological and artificial fliers must contend with aerial perturbations that are ubiquitous in the outdoor environment. Flapping fliers are generally least stable but also most maneuverable around the roll axis, yet our knowledge of roll control in biological fliers remains limited. Hummingbirds are suitable models for linking aerodynamic perturbations to flight control strategies, as these small, powerful fliers are capable of remaining airborne even in adverse wind conditions. We challenged hummingbirds to fly within a steady, longitudinally (streamwise) oriented vortex that imposed a continuous roll perturbation, measured wing kinematics and neuromotor activation of the flight muscles with synchronized high-speed video and electromyography and used computational fluid dynamics (CFD) to estimate the aerodynamic forces generated by observed wing motions. Hummingbirds responded to the perturbation with bilateral differences in activation of the main flight muscles while maintaining symmetry in most major aspects of wing motion, including stroke amplitude, stroke plane angle, and flapping frequency. Hummingbirds did display consistent bilateral differences in subtler wing kinematic traits, including wing rotation and elevation. CFD modeling revealed that asymmetric wing rotation was critical for attenuating the effects of the perturbation. The birds also augmented flight stabilization by adjusting body and tail posture to expose greater surface area to upwash than to the undesirable downwash. Our results provide insight into the remarkable capacity of hummingbirds to maintain flight control, as well as bio-inspiration for simple yet effective control strategies that could allow robotic fliers to contend with unfamiliar and challenging real-world aerial conditions. Both biological and artificial fliers must contend with aerial perturbations that are ubiquitous in the outdoor environment. Flapping fliers are generally least stable but also most maneuverable around the roll axis, yet our knowledge of roll control in biological fliers remains limited. Hummingbirds are suitable models for linking aerodynamic perturbations to flight control strategies, as these small, powerful fliers are capable of remaining airborne even in adverse wind conditions. We challenged hummingbirds to fly within a steady, longitudinally (streamwise) oriented vortex that imposed a continuous roll perturbation, measured wing kinematics and neuromotor activation of the flight muscles with synchronized high-speed video and electromyography and used computational fluid dynamics (CFD) to estimate the aerodynamic forces generated by observed wing motions. Hummingbirds responded to the perturbation with bilateral differences in activation of the main flight muscles while maintaining symmetry in most major aspects of wing motion, including stroke amplitude, stroke plane angle, and flapping frequency. Hummingbirds did display consistent bilateral differences in subtler wing kinematic traits, including wing rotation and elevation. CFD modeling revealed that asymmetric wing rotation was critical for attenuating the effects of the perturbation. The birds also augmented flight stabilization by adjusting body and tail posture to expose greater surface area to upwash than to the undesirable downwash. Our results provide insight into the remarkable capacity of hummingbirds to maintain flight control, as well as bio-inspiration for simple yet effective control strategies that could allow robotic fliers to contend with unfamiliar and challenging real-world aerial conditions. As flying animals navigate their habitats near the Earth’s surface, they contend with complex, unpredictable airflows that challenge their aerial stability. To remain airborne, flapping fliers need mechanisms for rapidly adjusting movements with respect to airflow perturbations [1Dickinson M.H. Farley C.T. Full R.J. Koehl M.A. Kram R. Lehman S. How animals move: an integrative view.Science. 2000; 288: 100-106Crossref PubMed Scopus (1140) Google Scholar, 2Ristroph L. Bergou A.J. Ristroph G. Coumes K. Berman G.J. Guckenheimer J. Wang Z.J. Cohen I. Discovering the flight autostabilizer of fruit flies by inducing aerial stumbles.Proc. Natl. Acad. Sci. USA. 2010; 107: 4820-4824Crossref PubMed Scopus (132) Google Scholar, 3Hedrick T.L. Cheng B. Deng X. Wingbeat time and the scaling of passive rotational damping in flapping flight.Science. 2009; 324: 252-255Crossref PubMed Scopus (220) Google Scholar]. Whether active or passive in nature, such mechanisms are likely subject to strong natural selection in biological fliers [4Norberg U.M. Rayner J.M.V. Ecological morphology and flight in bats (Mammalia; Chiroptera): wing adaptations, flight performance, foraging strategy and echolocation.Philos. Trans. R. Soc. B Biol. Sci. 1987; 316: 335-427Crossref Google Scholar] and are critical for sustained flight in artificial fliers [5Ramezani A. Chung S.J. Hutchinson S. A biomimetic robotic platform to study flight specializations of bats.Sci. Robot. 2017; 2: eaal2505Crossref PubMed Scopus (134) Google Scholar]. The literature on responses to gust perturbations and chaotic flow in biological fliers is rich. Prior studies have demonstrated the diverse strategies of insects, despite their small size and limited sensorimotor resources, as compared to vertebrate fliers. Passive mechanisms include self-righting through counter-torque produced by flapping [3Hedrick T.L. Cheng B. Deng X. Wingbeat time and the scaling of passive rotational damping in flapping flight.Science. 2009; 324: 252-255Crossref PubMed Scopus (220) Google Scholar] and passive inertial control provided by appendages [6Ristroph L. Ristroph G. Morozova S. Bergou A.J. Chang S. Guckenheimer J. Wang Z.J. Cohen I. Active and passive stabilization of body pitch in insect flight.J. R. Soc. Interface. 2013; 10: 20130237Crossref PubMed Scopus (90) Google Scholar]. Insect flight studies also showcase a wide array of active responses, including changes in stroke amplitude [7Vance J.T. Faruque I. Humbert J.S. Kinematic strategies for mitigating gust perturbations in insects.Bioinspir. Biomim. 2013; 8: 016004Crossref PubMed Scopus (57) Google Scholar], angle of attack (AoA) [6Ristroph L. Ristroph G. Morozova S. Bergou A.J. Chang S. Guckenheimer J. Wang Z.J. Cohen I. Active and passive stabilization of body pitch in insect flight.J. R. Soc. Interface. 2013; 10: 20130237Crossref PubMed Scopus (90) Google Scholar, 8Crall J.D. Chang J.J. Oppenheimer R.L. Combes S.A. Foraging in an unsteady world: bumblebee flight performance in field-realistic turbulence.Interface Focus. 2017; 7: 20160086Crossref PubMed Scopus (31) Google Scholar, 9Ortega-Jimenez V.M. Greeter J.S.M. Mittal R. Hedrick T.L. Hawkmoth flight stability in turbulent vortex streets.J. Exp. Biol. 2013; 216: 4567-4579Crossref PubMed Scopus (49) Google Scholar], angular rotation [7Vance J.T. Faruque I. Humbert J.S. Kinematic strategies for mitigating gust perturbations in insects.Bioinspir. Biomim. 2013; 8: 016004Crossref PubMed Scopus (57) Google Scholar], and wingbeat frequency [8Crall J.D. Chang J.J. Oppenheimer R.L. Combes S.A. Foraging in an unsteady world: bumblebee flight performance in field-realistic turbulence.Interface Focus. 2017; 7: 20160086Crossref PubMed Scopus (31) Google Scholar]. A particularly impressive example is the ability of hawkmoths to negotiate whirlwind perturbations through drastic stroke-to-stroke alterations of wing kinematics [10Ortega-Jimenez V.M. Mittal R. Hedrick T.L. Hawkmoth flight performance in tornado-like whirlwind vortices.Bioinspir. Biomim. 2014; 9: 025003Crossref PubMed Scopus (24) Google Scholar]. However, it remains largely unknown how vertebrate fliers, such as birds and bats, combine active and passive mechanisms to contend with aerial perturbations. Compared to insects, vertebrate fliers have more elaborate nervous systems that may confer greater neuromuscular control of their more articulated wing systems. Bats, for instance, harness inertial effects by asymmetrically folding their wings to perform acrobatic aerial maneuvers [11Bergou A.J. Swartz S.M. Vejdani H. Riskin D.K. Reimnitz L. Taubin G. Breuer K.S. Falling with style: bats perform complex aerial rotations by adjusting wing inertia.PLoS Biol. 2015; 13: e1002297Crossref PubMed Scopus (44) Google Scholar, 12Boerma D.B. Breuer K.S. Treskatis T.L. Swartz S.M. Wings as inertial appendages: how bats recover from aerial stumbles..J. Exp. Biol. 2019; 222: 204024Crossref Scopus (7) Google Scholar], which may also contribute to their perturbation responses. Birds have fewer distal wing joints than bats, which reduces their wing kinematic complexity and thus makes birds a more tractable system for understanding vertebrate control responses to aerial perturbations. Hummingbirds, in particular, are well-studied, small, powerful flyers that are highly amenable to wind tunnel experiments. Hummingbird wing kinematics [13Tobalske B.W. Warrick D.R. Clark C.J. Powers D.R. Hedrick T.L. Hyder G.A. Biewener A.A. Three-dimensional kinematics of hummingbird flight.J. Exp. Biol. 2007; 210: 2368-2382Crossref PubMed Scopus (196) Google Scholar] and muscle activity patterns [14Tobalske B.W. Biewener A.A. Warrick D.R. Hedrick T.L. Powers D.R. Effects of flight speed upon muscle activity in hummingbirds.J. Exp. Biol. 2010; 213: 2515-2523Crossref PubMed Scopus (31) Google Scholar, 15Altshuler D.L. Welch Jr., K.C. Cho B.H. Welch D.B. Lin A.F. Dickson W.B. Dickinson M.H. Neuromuscular control of wingbeat kinematics in Anna’s hummingbirds (Calypte anna).J. Exp. Biol. 2010; 213: 2507-2514Crossref PubMed Scopus (23) Google Scholar] in laminar flow have already been established across a range of forward flight speeds. Previous studies have also shown that hummingbirds can navigate unsteady wakes and turbulent air flow by altering stroke amplitude, frequency, and a range of other wing kinematic parameters [16Ortega-Jimenez V.M. Sapir N. Wolf M. Variano E.A. Dudley R. Into turbulent air: size-dependent effects of von Kármán vortex streets on hummingbird flight kinematics and energetics.Proc. Biol. Sci. 2014; 281: 20140180Crossref PubMed Scopus (45) Google Scholar, 17Ravi S. Crall J.D. McNeilly L. Gagliardi S.F. Biewener A.A. Combes S.A. Hummingbird flight stability and control in freestream turbulent winds.J. Exp. Biol. 2015; 218: 1444-1452Crossref PubMed Scopus (33) Google Scholar], as well as fanning their tails to actively maintain flight control [17Ravi S. Crall J.D. McNeilly L. Gagliardi S.F. Biewener A.A. Combes S.A. Hummingbird flight stability and control in freestream turbulent winds.J. Exp. Biol. 2015; 218: 1444-1452Crossref PubMed Scopus (33) Google Scholar]. This wealth of background data on hummingbird flight makes them an ideal model system for examining neuromuscular flight control in the face of challenging, aerial perturbations. Flight control in the face of aerodynamic perturbations involves both passive and active mechanisms [1Dickinson M.H. Farley C.T. Full R.J. Koehl M.A. Kram R. Lehman S. How animals move: an integrative view.Science. 2000; 288: 100-106Crossref PubMed Scopus (1140) Google Scholar]. However, it remains unclear exactly how neuromotor control drives active responses to flight perturbations. Neuromotor modulation may be key for shaping both kinematic and behavioral responses to perturbations [14Tobalske B.W. Biewener A.A. Warrick D.R. Hedrick T.L. Powers D.R. Effects of flight speed upon muscle activity in hummingbirds.J. Exp. Biol. 2010; 213: 2515-2523Crossref PubMed Scopus (31) Google Scholar, 18Biewener A.A. Muscle function in avian flight: achieving power and control.Philos. Trans. R. Soc. B Biol. Sci. 2011; 366: 1496-1506Crossref PubMed Scopus (70) Google Scholar]. Studies of small (mainly invertebrate) fliers have begun to “close the loop” by linking kinematics to neuromotor control [19Balint C.N. Dickinson M.H. The correlation between wing kinematics and steering muscle activity in the blowfly Calliphora vicina.J. Exp. Biol. 2001; 204: 4213-4226Crossref PubMed Google Scholar, 20Sato H. Vo Doan T.T. Kolev S. Huynh N.A. Zhang C. Massey T.L. van Kleef J. Ikeda K. Abbeel P. Maharbiz M.M. Deciphering the role of a coleopteran steering muscle via free flight stimulation.Curr. Biol. 2015; 25: 798-803Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar, 21Fernández M.J. Springthorpe D. Hedrick T.L. Neuromuscular and biomechanical compensation for wing asymmetry in insect hovering flight.J. Exp. Biol. 2012; 215: 3631-3638Crossref PubMed Scopus (39) Google Scholar] and (via empirical or computational fluid dynamics [CFD] approaches) to the production of aerodynamic forces, in still air as well as unsteady, perturbed flow [9Ortega-Jimenez V.M. Greeter J.S.M. Mittal R. Hedrick T.L. Hawkmoth flight stability in turbulent vortex streets.J. Exp. Biol. 2013; 216: 4567-4579Crossref PubMed Scopus (49) Google Scholar, 10Ortega-Jimenez V.M. Mittal R. Hedrick T.L. Hawkmoth flight performance in tornado-like whirlwind vortices.Bioinspir. Biomim. 2014; 9: 025003Crossref PubMed Scopus (24) Google Scholar, 16Ortega-Jimenez V.M. Sapir N. Wolf M. Variano E.A. Dudley R. Into turbulent air: size-dependent effects of von Kármán vortex streets on hummingbird flight kinematics and energetics.Proc. Biol. Sci. 2014; 281: 20140180Crossref PubMed Scopus (45) Google Scholar, 22Vance J.T. Altshuler D.L. Dickson W.B. Dickinson M.H. Roberts S.P. Hovering flight in the honeybee Apis mellifera: kinematic mechanisms for varying aerodynamic forces.Physiol. Biochem. Zool. 2014; 87: 870-881Crossref PubMed Scopus (21) Google Scholar]. For vertebrate fliers, some studies have begun linking kinematics to motor control [14Tobalske B.W. Biewener A.A. Warrick D.R. Hedrick T.L. Powers D.R. Effects of flight speed upon muscle activity in hummingbirds.J. Exp. Biol. 2010; 213: 2515-2523Crossref PubMed Scopus (31) Google Scholar, 15Altshuler D.L. Welch Jr., K.C. Cho B.H. Welch D.B. Lin A.F. Dickson W.B. Dickinson M.H. Neuromuscular control of wingbeat kinematics in Anna’s hummingbirds (Calypte anna).J. Exp. Biol. 2010; 213: 2507-2514Crossref PubMed Scopus (23) Google Scholar, 23Mahalingam S. Welch Jr., K.C. Neuromuscular control of hovering wingbeat kinematics in response to distinct flight challenges in the ruby-throated hummingbird, Archilochus colubris.J. Exp. Biol. 2013; 216: 4161-4171Crossref PubMed Scopus (14) Google Scholar, 24Konow N. Cheney J.A. Roberts T.J. Iriarte-Díaz J. Breuer K.S. Waldman J.R.S. Swartz S.M. Speed-dependent modulation of wing muscle recruitment intensity and kinematics in two bat species.J. Exp. Biol. 2017; 220: 1820-1829Crossref PubMed Scopus (11) Google Scholar] and estimating the aerodynamic forces that result via CFD [18Biewener A.A. Muscle function in avian flight: achieving power and control.Philos. Trans. R. Soc. B Biol. Sci. 2011; 366: 1496-1506Crossref PubMed Scopus (70) Google Scholar, 25Song J. Luo H. Hedrick T.L. Three-dimensional flow and lift characteristics of a hovering ruby-throated hummingbird.J. R. Soc. Interface. 2014; 11: 20140541Crossref PubMed Scopus (62) Google Scholar] and empirical associations [26Reynolds K.V. Thomas A.L.R. Taylor G.K. Wing tucks are a response to atmospheric turbulence in the soaring flight of the steppe eagle Aquila nipalensis.J. R. Soc. Interface. 2014; 11: 20140645Crossref PubMed Scopus (33) Google Scholar]. However, these approaches have yet to be combined for studies of vertebrate fliers subjected to aerodynamic perturbations during flight. Here, we generated a nominally time-invariant vortex that is oriented longitudinally (with its core oriented streamwise along the axis of the wind tunnel) to impose an extreme and continuous aerodynamic perturbation on flying hummingbirds (Archilochus colubris). The positioning of the vortex core relative to a feeder means that birds experience upwash on one wing and downwash on the other, which induces a strong, continuous roll perturbation (Figure 1). Within this challenging yet predictable aerial environment, we analyzed the response of subjects in terms of both wing kinematics and neuromuscular control, using 3D high-speed video to quantify kinematics and electromyography to determine neuromotor modulation of the pectoralis (primary downstroke muscle) and supracoracoideus (primary upstroke muscle) with respect to airflow conditions. We then use CFD simulations to assess the functional role of observed changes in wing motions. We first assessed the impact of a longitudinal vortex created in the CFD domain, nominally similar to experiment, on a hummingbird flying with steady wing kinematics. However, performing CFD simulations with a longitudinal vortex that matches experimental measurements as well as a flapping bird downstream is currently not feasible. Therefore, we conducted further simulations in steady (laminar) flow using the kinematics measured on birds flying in a longitudinal vortex. We hypothesized that deploying the observed kinematics in laminar flow should result in bilaterally asymmetric lift production and a roll toque in the direction opposite to that imposed on real birds by the vortex flow. The CFD model is also used to perform comparative analysis of the contribution of individual kinematic changes to overall stabilization of the perturbation by modeling different parameters in isolation. This workflow allows us to identify the key response parameters for flight stabilization and disturbance rejection. Studies of aerial perturbations have historically been focused on yaw and pitch perturbations [6Ristroph L. Ristroph G. Morozova S. Bergou A.J. Chang S. Guckenheimer J. Wang Z.J. Cohen I. Active and passive stabilization of body pitch in insect flight.J. R. Soc. Interface. 2013; 10: 20130237Crossref PubMed Scopus (90) Google Scholar, 27Cheng B. Deng X. Hedrick T.L. The mechanics and control of pitching manoeuvres in a freely flying hawkmoth (Manduca sexta).J. Exp. Biol. 2011; 214: 4092-4106Crossref PubMed Scopus (115) Google Scholar, 28Cheng B. Tobalske B.W. Powers D.R. Hedrick T.L. Wethington S.M. Chiu G.T.C. Deng X. Flight mechanics and control of escape manoeuvres in hummingbirds. I. Flight kinematics.J. Exp. Biol. 2016; 219: 3518-3531Crossref PubMed Scopus (29) Google Scholar]. However, roll remains a vital maneuvering and stability mode with a smaller moment of inertia than the pitch and yaw axes in many flying animals [29Combes S.A. Dudley R. Turbulence-driven instabilities limit insect flight performance.Proc. Natl. Acad. Sci. USA. 2009; 106: 9105-9108Crossref PubMed Scopus (93) Google Scholar]. Accordingly, we hypothesize that a strong, flow-induced roll torque will elicit bilaterally asymmetric wing kinematics to produce a compensatory counter-torque. However, determining whether observed kinematic changes are entirely passive (i.e., induced by the external flow) or in fact are generated actively by the bird requires direct measurement of the neuromotor response. Previous work has shown that voluntary maneuvering during yaw turns and abrupt course changes in hummingbirds and cockatoos involve no bilateral variation in activation (duration of neural stimulation) or recruitment (measured as electromyogram [EMG] amplitude, a proxy for the number of motor units and volume of muscle activated) of the largest flight muscles (pectoralis and supracoracoideus) [30Altshuler D.L. Quicazán-Rubio E.M. Segre P.S. Middleton K.M. Wingbeat kinematics and motor control of yaw turns in Anna’s hummingbirds (Calypte anna).J. Exp. Biol. 2012; 215: 4070-4084Crossref PubMed Scopus (34) Google Scholar, 31Hedrick T.L. Usherwood J.R. Biewener A.A. Low speed maneuvering flight of the rose-breasted cockatoo (Eolophus roseicapillus). II. Inertial and aerodynamic reorientation.J. Exp. Biol. 2007; 210: 1912-1924Crossref PubMed Scopus (45) Google Scholar]. However, as hummingbirds engage in unsteady flight, e.g., during mating displays, they use significant asymmetry in wing kinematics [30Altshuler D.L. Quicazán-Rubio E.M. Segre P.S. Middleton K.M. Wingbeat kinematics and motor control of yaw turns in Anna’s hummingbirds (Calypte anna).J. Exp. Biol. 2012; 215: 4070-4084Crossref PubMed Scopus (34) Google Scholar, 32Cheng B. Tobalske B.W. Powers D.R. Hedrick T.L. Wethington S.M. Chiu G.T.C. Deng X. Flight mechanics and control of escape manoeuvres in hummingbirds. I. Flight kinematics.J. Exp. Biol. 2016; 219: 3518-3531Crossref PubMed Scopus (44) Google Scholar, 33Mahalingam S. Welch Jr., K.C. Neuromuscular control of hovering wingbeat kinematics in response to distinct flight challenges in the ruby-throated hummingbird, Archilochus colubris.J. Exp. Biol. 2013; 216: 4161-4171Crossref PubMed Scopus (16) Google Scholar] that are associated with variations in the recruitment pattern of major flight muscles and consistent with feedforward control [30Altshuler D.L. Quicazán-Rubio E.M. Segre P.S. Middleton K.M. Wingbeat kinematics and motor control of yaw turns in Anna’s hummingbirds (Calypte anna).J. Exp. Biol. 2012; 215: 4070-4084Crossref PubMed Scopus (34) Google Scholar]. The upwash produced by our longitudinal vortex should reduce the need for aerodynamic force production by the wing subjected to it. Therefore, we hypothesize that hummingbirds will respond by displaying lower wing-stroke amplitude and/or a longer downstroke duration (i.e., slower velocity) in this wing (kinematic response), driven by decreased muscle activation and recruitment (EMG) of the associated flight muscles (neuromotor response). This combination would be expected to result in reduced aerodynamic force production from this wing, whereas for the wing subjected to the downwash of the longitudinal vortex, we predict increases in the same kinematic and neuromotor parameters to provide increased production of aerodynamic force. The difference in force production between the two wings should result in a stabilizing counter-torque on the body. Mean wingbeat frequency, stroke amplitude, and stroke-plane angle employed by birds flying in the vortex and laminar flow conditions were statistically indistinguishable (tested for differences between wings within each flow treatment, as well as across the different flow conditions, with ANOVA; all p > 0.15; Table S1). There were also no statistically significant differences in mean angular wing position across airflow conditions (Figure 2C). However, during flight in the longitudinal vortex, all four subjects displayed consistent, bilateral differences in wing elevation and rotation patterns. In laminar flow, there was no bilateral asymmetry in the mean or instantaneous angles of wing elevation and rotation, whereas during flight in the longitudinal vortex, the kinematics of a given wing were strongly dependent on the local airflow condition (either upwash or downwash; Figures 2D and 2E). Due to asymmetries in wing elevation patterns between the two wings, the path of the leading edge of the wing resembled a figure eight pattern when in the upwash but an oval path when in the downwash of the longitudinal vortex (Figures 2F–2H). Except for early in the downstroke, when wing rotation was similar among all three flow conditions, overall wing rotation was greater for the wing in upwash than for the wing in downwash (Figures 2E–2H). The birds maintained these asymmetries in wing kinematics throughout the entire duration (5- to 10-s feeding bouts) of their flight in the longitudinal vortex flow. At 75% span, the wing in the vortex downwash operated at higher AoA (Figure S3) during the downstroke as compared to the wing in laminar and vortex upwash conditions. At the same spanwise location, during upstroke, nominally similar AoA was noted for both downwash and laminar flow conditions, although AoA was lower for the wing in the upwash (Figure S4). No significant differences were observed in mean body roll or pitch angle for any of the flight conditions. However, the mean yaw angle of the body differed significantly between laminar flow and clockwise versus counterclockwise vortex conditions (F2,16 = 4.51; p < 0.001; Figure 3A). In steady, laminar wind, the birds were aligned with the longitudinal axis of the wind tunnel, but when confronted with the clockwise vortex, they yawed negatively (to their right), and this pattern reversed when they flew in the counterclockwise vortex condition (see Figure 3 for illustration). In addition, tail fan angle during flight in the vortex was greater than during flight in laminar flow flight for all birds (F2,16 = 5.51; p < 0.0001; Figure 3B). CFD simulation of the hummingbird flying with symmetric kinematics in the relatively mild vortex created by the upstream vortex generator (case 0; Figure S4) indeed caused a large roll torque on the bird (Table 1) that would require compensation. Simulation under laminar conditions of the numerical hummingbird with wing kinematics measured in laminar flow (case 1) resulted in the generation of adequate vertical aerodynamic force to establish weight support (Figures 4A and 4D ; Video S2A; Table 1). Weight support was also demonstrated in the simulation using the wing kinematics measured on birds flying in the clockwise vortex, but because the kinematics were tested with laminar inflow in the simulation, they produced a lift imbalance between the wings (case 2; see Figures 4B and 4D; Video S2B; Table 1). The kinematics measured from the wing immersed in downwash produced higher lift compared to the kinematics of the wing in upwash, creating a strong, counterclockwise roll torque, as expected (Table 1; see velocity contours in Figure 4). The torques measured in the CFD simulation are a representation of those produced by the birds when flying in the vortex; in the longitudinal vortex flow experienced by the real birds, this roll torque induced by asymmetric wing kinematics would counteract the torque induced by external flow.Table 1Kinematics Variables Used in the Different Cases for Numerical Simulations and the Mean Vertical Force and Roll Torque ProducedCaseInflow ConditionWing Kinematics ParametersMean Vertical Force (mN)Mean Roll Torque, mN ⋅ m−1PositionElevationRotation0↻⇇⇇⇇70.1−408.41⇇⇇⇇⇇72.7–2⇇↻↻↻67.2788.93⇇⇇↻⇇70.5−273.04⇇⇇⇇↻65.2793.4Case 0 is a simulation of the hummingbird flying in the longitudinal vortex with kinematics measured in the laminar flow condition; see Figure S4 for flow field comparison and snapshot of simulation. Cases 1 and 2 are simulations of hummingbird flight in steady wind with kinematics measured in the laminar flow condition (1) and in a clockwise vortex (2). Case 3 is a kinematic hybrid between laminar flow and clockwise vortex conditions with wing elevation angles from the clockwise vortex condition and other parameters as measured in laminar flow. Case 4 is another kinematic hybrid with wing elevation and position angles from the laminar flow condition and rotation angles from the clockwise vortex. Open table in a new tab Case 0 is a simulation of the hummingbird flying in the longitudinal vortex with kinematics measured in the laminar flow condition; see Figure S4 for flow field comparison and snapshot of simulation. Cases 1 and 2 are simulations of hummingbird flight in steady wind with kinematics measured in the laminar flow condition (1) and in a clockwise vortex (2). Case 3 is a kinematic hybrid between laminar flow and clockwise vortex conditions with wing elevation angles from the clockwise vortex condition and other parameters as measured in laminar flow. Case 4 is another kinematic hybrid with wing elevation and position angles from the laminar flow condition and rotation angles from the clockwise vortex. eyJraWQiOiI4ZjUxYWNhY2IzYjhiNjNlNzFlYmIzYWFmYTU5NmZmYyIsImFsZyI6IlJTMjU2In0.eyJzdWIiOiJjMzYyNDQ1YWY5NTUzYjY1NWU1YjkxODhlNDA0YTE4MyIsImtpZCI6IjhmNTFhY2FjYjNiOGI2M2U3MWViYjNhYWZhNTk2ZmZjIiwiZXhwIjoxNjc4Njk4OTI3fQ.cNjkEwPLhdkZWWDVgZXgWvVqkU6OOoBHZaCmfIg8QeYXEL4GfBfk6pDvjeVcM0u1opCxwRimh_X-c7toiG4v5H17zv5btIxN1EqMZfSbiCm_7ihYEYomla97I19Qj7vPWIcoIzcKZKSXqSvEpL2C7ZpznjMcIkhaSTLqyHyuViVIDxovCf3XwcrM7T3_WvjDNq-wLPMTZVjoXR6SFtkW7AeWKdgkcQinEFnYaEcsIi3TfUzFmNa4d0KSBsnqNYZ0eB9N5hXTd-llUeHAwMEWihoBvQJjMDi79kHPFrNR0Vff8YTvseum8mD7TlfXJPKn6gX-4b8G6V4x4n2IulG9zQ Download .mp4 (8.54 MB) Help with .mp4 files Video S2Animation of the CFD Simulation of Hummingbirds, Related to Figures 2 and 4, and Reresented as a 2x2 Panel Video for Cases 1-4. CFD simulations of birds flying with kinematics that were a hybrid between those measured in laminar flow and in the vortex condition allowed us to comparatively assess the significance of each kinematic parameter that differed between the wings during the perturbation response. These simulations revealed that employing bilateral asymmetry in wing rotation angles (matching those measured in the vortex condition) while all other parameters were symmetric (as in the laminar flow condition) produced a vertical force similar to that in laminar flow and approximately 80% of the roll torque produced by fully asymmetric kinematics (cases 2 and 4; Table 1). This roll torque was a result of the wing rotation angle in downwash producing higher lift, and the resulting flow field closely resembled that of experimentally measured kinematics (compare Figures 4B and 4D; Video S2). Simulation of hybrid kinematics involving bilateral asymmetry in the angle of wing elevation alone (case 3) produced a" @default.
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• W2997502877 date "2020-01-01" @default.
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• W2997502877 title "Modulation of Flight Muscle Recruitment and Wing Rotation Enables Hummingbirds to Mitigate Aerial Roll Perturbations" @default.
• W2997502877 cites W1925405177 @default.
• W2997502877 cites W1966708318 @default.
• W2997502877 cites W1967332823 @default.
• W2997502877 cites W1971392077 @default.
• W2997502877 cites W1992941941 @default.
• W2997502877 cites W2008541567 @default.
• W2997502877 cites W2013070970 @default.
• W2997502877 cites W2019604338 @default.
• W2997502877 cites W2037234162 @default.
• W2997502877 cites W2043213386 @default.
• W2997502877 cites W2072544504 @default.
• W2997502877 cites W2073116181 @default.
• W2997502877 cites W2073346639 @default.
• W2997502877 cites W2079283009 @default.
• W2997502877 cites W2093937828 @default.
• W2997502877 cites W2095443583 @default.
• W2997502877 cites W2095514211 @default.
• W2997502877 cites W2100125836 @default.
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