Performance of a wing with nonuniform flexibility in hovering flight

Shoele, Kourosh; Zhu, Qiang

doi:10.1063/1.4802193

Cited by 61 publications

(49 citation statements)

References 42 publications

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“…As such, the simulations can only examine a handful of different material distributions, typically chosen to mimic real insect wings. These simulations demonstrate definite performance advantages of insect-like distributions over stiff wings [63,82]. However, it remains to be seen whether these distributions are optimal in any sense, as the infinite-dimensional space of arbitrary material distribution remains largely unexplored by these methods.…”

Section: Introductionmentioning

confidence: 99%

“…Research on heterogeneous wings has appeared more recently [85,64,63,82,17,48,47,66]. The majority of these studies focus on insect flight and, more specifically, simulating the coupled aeroelastic dynamics of compositionally complex wings [64,63,82,66].…”

Section: Introductionmentioning

confidence: 99%

“…The majority of these studies focus on insect flight and, more specifically, simulating the coupled aeroelastic dynamics of compositionally complex wings [64,63,82,66]. Since they employ direct numerical simulation (DNS) of the coupled Navier-Stokes/elastic-body partial differential equations (PDEs), the computational cost of a single simulation can be quite high.…”

Section: Introductionmentioning

confidence: 99%

“…These appendages deform significantly when actuated, which can provide a number of performance benefits. In addition, natural wings and fins often exhibit complex material compositions, with elastic properties that can be highly nonuniform and even anisotropic [43,85,82,48]. Understanding how biology exploits material heterogeneity could significantly advance the design of artificial devices.…”

Section: Introductionmentioning

confidence: 99%

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A fast Chebyshev method for simulating flexible-wing propulsion

Moore¹

2017

Journal of Computational Physics

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We develop a highly efficient numerical method to simulate small-amplitude flapping propulsion by a flexible wing in a nearly inviscid fluid. We allow the wing's elastic modulus and mass density to vary arbitrarily, with an eye towards optimizing these distributions for propulsive performance. The method to determine the wing kinematics is based on Chebyshev collocation of the 1D beam equation as coupled to the surrounding 2D fluid flow. Through small-amplitude analysis of the Euler equations (with trailing-edge vortex shedding), the complete hydrodynamics can be represented by a nonlocal operator that acts on the 1D wing kinematics. A class of semi-analytical solutions permits fast evaluation of this operator with O (N log N ) operations, where N is the number of collocation points on the wing. This is in contrast to the minimum O N 2 cost of a direct 2D fluid solver. The coupled wing-fluid problem is thus recast as a PDE with nonlocal operator, which we solve using a preconditioned iterative method. These techniques yield a solver of nearoptimal complexity, O (N log N ), allowing one to rapidly search the infinite-dimensional parameter space of all possible material distributions and even perform optimization over this space.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A fast Chebyshev method for simulating flexible-wing propulsion

Moore¹

2017

Journal of Computational Physics

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“…Further research [63,64] has illustrated that the performance of a rigid flapping wing can be improved significantly by adding some level of flexibility to the wing surface. For achieving such performance enhancement, both passive and active flow control mechanisms have been studied, and some examples are reviewed here.…”

Section: Effect Of Propulsor Morphing Kinematicsmentioning

confidence: 99%

Low Dimensional Morphology Analysis and Computational Optimization of Flapping Propulsors in Nature

Ren¹

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Flapping propulsion is widely adopted by many natural flyers/swimmers, including insects, birds, fishes, and marine mammals. It offers an attractive alternative to conventional propulsion methods for future bio-inspired aerial/underwater systems.However, due to lack of effective technology of studying the highly complex propulsor morphing kinematics and its associated aero/hydrodynamics, achieving biological levels of aero/hydro-performance in bio-inspired flapping propulsor design has proven elusive.Here, an integrated experimental and computational methodology has been developed to systematically study the flapping propulsion system in nature. The goal is to advance the fundamental knowledge of biological fluid dynamics in animal flight/swimming, and provide guidance for future optimal designs of bio-inspired flapping propulsors.The current dissertation consists of two parts, tools development and analysis of propulsion systems. In the first part, the integrated methodology is introduced, and the corresponding major contributions of the work are: (1) a highly versatile and accurate jointbased surface reconstruction method is developed to quantify the propulsor flexion and body kinematics of animals in free flight/swimming; (2) a spherical-coordinates-based singular value decomposition (SSVD) method is developed to perform low dimensional morphology analysis of flapping propulsors in nature; (3) an immersed boundary method for deformable attaching bodies (IBM-DAB) is developed to handle direct numerical simulations (DNS) in some extreme situations which are commonly exist in nature, including solid body with sharp edge and with deformable attaching membrane bodies; (4) ii a highly efficient gradient-based parallel curve searching optimizer is developed to explore design space of flapping propulsors.In the second part, the aforementioned integrated approach is applied to study several problems. We first investigate the optimal configurations of several morphological parameters, which control the dynamic camber and twisting of the propulsors, on aerodynamic performance using simplified canonical models. Optimizations of dynamic camber formation of 2D pitching-plunging plates and dynamic twisting of 3D pitchingrolling plates are performed. It is found that the morphological parameters play important roles in the plate aerodynamic performance and wake structures. Comparing to completely rigid plate, the thrust production and propulsive efficiency of optimized plates can be improved up to 29.1% and 43.1%, respectively. The associated flow mechanisms are found to be the improved strength and attachment of leading-edge vortex (LEV).Next, the integrated approach is used to study the complex morphing propulsor kinematics and the associated aero/hydrodynamics of natural flyers/swimmers in relatively simple motions, such as hovering and fast swimming. The SSVD analysis of the forewing motion of a hovering dragonfly reveals that the complicated wing motion can be represented by a low dimensional model contains two ...

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Effect of curvature variations on the hydrodynamic performance of heaving and pitching foils

van Rees

2024

Theor. Comput. Fluid Dyn.

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The use of heaving and pitching fins for underwater propulsion of engineering devices poses an attractive outlook given the efficiency and adaptability of natural fish. However, significant knowledge gaps need to be bridged before biologically inspired propulsion is able to operate at competitive performances in a practical setting. One of these relates to the design of structures that can leverage passive deformation and active morphing in order to achieve optimal hydrodynamic performance. To provide insights into the performance improvements associated with passive and active fin deformations, we provide here a systematic numerical investigation in the thrust, power, and efficiency of 2D heaving and pitching fins with imposed curvature variations. The results show that for a given chordline kinematics, the use of curvature can improve thrust by 70% or efficiency by 35% over a rigid fin. Maximum thrust is achieved when the camber variations are synchronized with the maximum heave velocity, increasing the overall magnitude of the force vector while increasing efficiency as well. Maximum efficiency is achieved when camber is applied during the first half of the stroke, tilting the force vector to create thrust earlier in the cycle than a comparable rigid fin. Overall, our results demonstrate that curving fins are consistently able to significantly outperform rigid fins with the same chord line kinematics on both thrust and hydrodynamic efficiency.

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Performance of a wing with nonuniform flexibility in hovering flight

Cited by 61 publications

References 42 publications

A fast Chebyshev method for simulating flexible-wing propulsion

A fast Chebyshev method for simulating flexible-wing propulsion

Low Dimensional Morphology Analysis and Computational Optimization of Flapping Propulsors in Nature

Effect of curvature variations on the hydrodynamic performance of heaving and pitching foils

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