Effect of chord flexure on aerodynamic performance of a flapping wing

Le, Tuyen Quang; Ko, Jin Hwan; Byun, Doyoung; Park, Soo Hyung; Park, Hoon Cheol

doi:10.1016/s1672-6529(09)60196-7

Cited by 22 publications

(15 citation statements)

References 9 publications

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“…Then, the aerodynamic power was calculated by the scalar products of the angular velocity and the aerodynamic torque of the wing. The accuracy of our flow solver in analysing a flapping wing was validated in previous works [34,35]. Moreover, we performed a simulation of a fruitfly model during hovering as the benchmark for the three-dimensional flapping simulation.…”

Section: Evaluation Of Force and Validation Of Methodsmentioning

confidence: 92%

Improvement of the aerodynamic performance by wing flexibility and elytra–hind wing interaction of a beetle during forward flight

Truong

Park

et al. 2013

J. R. Soc. Interface.

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In this work, the aerodynamic performance of beetle wing in free-forward flight was explored by a three-dimensional computational fluid dynamics (CFDs) simulation with measured wing kinematics. It is shown from the CFD results that twist and camber variation, which represent the wing flexibility, are most important when determining the aerodynamic performance. Twisting wing significantly increased the mean lift and camber variation enhanced the mean thrust while the required power was lower than the case when neither was considered. Thus, in a comparison of the power economy among rigid, twisting and flexible models, the flexible model showed the best performance. When the positive effect of wing interaction was added to that of wing flexibility, we found that the elytron created enough lift to support its weight, and the total lift (48.4 mN) generated from the simulation exceeded the gravity force of the beetle (47.5 mN) during forward flight.

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Section: Evaluation Of Force and Validation Of Methodsmentioning

confidence: 92%

Improvement of the aerodynamic performance by wing flexibility and elytra–hind wing interaction of a beetle during forward flight

Truong

Park

et al. 2013

J. R. Soc. Interface.

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“…The in-house solver KFLOW [26] was used for this purpose. This solver was previously validated in various studies of unsteady rotor analysis [27,28], jet interaction [29], pitching airfoil in the dynamic stall regime [30], and design applications [31,32]. Based on the objectives of the present study, the flux difference splitting scheme with Harten's entropy fix [33] method for the inviscid flux vector can be written as shown in Eq.…”

Section: B Navier-stokes' Solutionsmentioning

confidence: 99%

“…Figure 10 shows the 27 selected planform variables (the chord length c, the twist angle ϕ at 13 different radial locations in the spanwise direction, and the blade radius), which are represented as the design vector X. The spanwise locations (5,10,15,20,30,40,55,65,75,85,90,95, and 100% of the blade radius) were clustered around the root and tip of blade. The distribution of the values of the twist angles and the chord lengths are plotted in Fig.…”

Section: B Sensitivity Study For Design Parametersmentioning

confidence: 99%

Design of Efficient Propellers Using Variable-Fidelity Aerodynamic Analysis and Multilevel Optimization

Kwon

Choi

et al. 2015

Journal of Propulsion and Power

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A multilevel design optimization framework was developed for the aerodynamic design of an electric aerial vehicle propeller in cruise conditions. The objective was to determine the optimum propeller shape to minimize torque at a given required thrust level and thus maximize overall propeller efficiency. A key concept of the design is the sequential application of a three-dimensional planform and two-dimensional section designs iteratively to make the best use of the complementary characteristics of gradient-free and gradient-based optimization strategies and the corresponding parameterization of the design space. Variable-fidelity aerodynamic analyses of blade element momentum theory and Navier-Stokes solutions were used to achieve computational efficiency and high accuracy. First, the optimal planform shape was determined by adjusting radius, twist angle, and chord lengths of the blade. Subsequently, the sectional airfoil design was performed at several spanwise locations. Given the new airfoil sections, the planform was redesigned to consider three-dimensional flow effects. The final optimized propeller design was validated using three-dimensional Navier-Stokes flow solvers and was tested in a wind-tunnel facility. Propeller efficiency was found to be improved by 5.7%. Finally, the fluid-structure interaction was analyzed to confirm that a required safety factor was ensured. Nomenclature a = axial induction factor a 0 = tangential induction factor C Q = torque coefficient, TQ∕ρn 2 D 5 C T = thrust coefficient, TH∕ρn 2 D 4 c = chord length at section of rotor blades, m D = diameter of rotor disk plane, m J = advance ratio, equal to V ∞ ∕nD n = rotational velocity, rotations∕s r = radius of rotor disk plane, m TH = thrust, N TQ = torque, N · m t∕c = thickness of section of rotor blades normalized by its chord length Vrel = relative velocity, m∕s V ∞ = freestream velocity, m∕s x LE = leading-edge location η = propeller efficiency, equal to JC T ∕2πC Q ϕ = twist angle at section of rotor blades, deg ω = rotational velocity, rotations∕ min

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“…Attempts to evaluate the role of propulsor bending on thrust production have been met with conflicting results. For example, although some empirical [8][9][10] , modelling [11][12][13] and computational studies [14][15][16][17] have indicated that flexible propulsors may permit higher thrust production than rigid counterparts, other evidence indicates that flexibility may sometimes lessen or prevent thrust production 10,18,19 . Evaluation of these results has been complicated by a lack of common bending criteria to guide experimental design.…”

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confidence: 99%

Bending rules for animal propulsion

et al. 2014

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Animal propulsors such as wings and fins bend during motion and these bending patterns are believed to contribute to the high efficiency of animal movements compared with those of man-made designs. However, efforts to implement flexible designs have been met with contradictory performance results. Consequently, there is no clear understanding of the role played by propulsor flexibility or, more fundamentally, how flexible propulsors should be designed for optimal performance. Here we demonstrate that during steady-state motion by a wide range of animals, from fruit flies to humpback whales, operating in either air or water, natural propulsors bend in similar ways within a highly predictable range of characteristic motions. By providing empirical design criteria derived from natural propulsors that have convergently arrived at a limited design space, these results provide a new framework from which to understand and design flexible propulsors.

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Effect of chord flexure on aerodynamic performance of a flapping wing

Cited by 22 publications

References 9 publications

Improvement of the aerodynamic performance by wing flexibility and elytra–hind wing interaction of a beetle during forward flight

Improvement of the aerodynamic performance by wing flexibility and elytra–hind wing interaction of a beetle during forward flight

Design of Efficient Propellers Using Variable-Fidelity Aerodynamic Analysis and Multilevel Optimization

Bending rules for animal propulsion

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