Oscillatory motions of a prestrained compliant membrane caused by fluid–membrane interaction

Molki, Majid; Breuer, Kenneth S.

doi:10.1016/j.jfluidstructs.2009.11.003

Cited by 32 publications

(12 citation statements)

References 16 publications

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“…The Reynolds number plays a more subtle role in the operational range of a wing along its We-z curve. In general, decreasing the Reynolds number moves the operating point of the wing along its We-z curve toward the origin, meaning less camber and less lift, a trend that has been reported in the literature 8,9 and is attributed to the changes in the boundary layer. The inability to account for these Reynolds number effects is another shortcoming of potential flow-based aerodynamic models.…”

Section: A Static Performancesupporting

confidence: 59%

“…Our approach to the computational model is similar in approach to the previous numerical works discussed: 5,9,21 A structural solver receives a pressure distribution from a flow solver and computes a membrane shape. Then, the structural solver informs the flow solver of a new shape.…”

Section: Computational Modelmentioning

confidence: 99%

“…2D steady laminar flow, turbulent flow, 3D unsteady, etc..), and then to solve the problem numerically by coupling a structural solver to a fluid dynamical solver. [5][6][7][8][9][10] As an example, Smith and Shyy 5 modeled the membrane airfoil as a two dimensional linear elastic membrane governed by the Young-Laplace equation. In their calculations, they assigned the membrane with a large modulus-sufficiently large to make the wing approximately inextensible-and excess length, and coupled the membrane solver with a Reynolds-averaged Navier-Stokes solver to compute equilibrium 2D configurations for the sail-like wing.…”

Section: Introductionmentioning

confidence: 99%

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Shape, lift, and vibrations of highly compliant membrane wings

Waldman

Breuer

2013

43rd Fluid Dynamics Conference

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Membrane wings are common in flying animals such as bats, lemurs, flying squirrels, and pterosaurs, as well as in low Reynolds number Micro Air Vehicles. Vortices shed from the sharp leading and trailing edges and wingtips of membrane wings, and the vortex interactions with the membrane play an important role in the wing's performance. With compliant membrane wings that are initially tension-free at rest, there are two issues to consider: (a) the static relationship between the net aerodynamic forces and the bulk wing deformation, and (b) the interaction between the membrane dynamics and unsteady flow structures. We present a simple model of the finite deformation and natural frequency of an initially tension-free membrane wing, which depends only on an aeroelastic parameter. We extend our theory with a computer model that accounts for nonuniform chordwise load. We conduct experiments on low aspect ratio membrane wings with different support structures and thicknesses, over a broad range of freestream velocities and angles of attack. We measure wing shape and dynamics, aerodynamic force, and the wake, and find good agreement between the experimental results, the computer model, and our theoretical model. Membrane deformation affects the membrane vibration modes, which in turn affects the coupling between the membrane and vortex shedding. Wings with different wingtip support, but similar stiffness show similar static behavior, but exhibit markedly different dynamic behavior.

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Section: A Static Performancesupporting

confidence: 59%

Section: Computational Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Shape, lift, and vibrations of highly compliant membrane wings

Waldman

Breuer

2013

43rd Fluid Dynamics Conference

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“…6 Considerable effort has been devoted toward flexible wings for such designs, following the bird flight such as bats. [7][8][9] However, providing fundamental analysis explaining resultant increase in propulsion efficiency or thrust owing to flexibility has been a challenge due to the complexity of the fluid-structure interaction problem. Oscillating foils with chordwise or spanwise flexibility have been studied using experiments 3-5, 10, 11 as well as simulations 1,[12][13][14][15][16][17] to show positive benefits of flexibility on performance.…”

Section: Introductionmentioning

confidence: 99%

Low Reynolds Number Flow Dynamics of a Thin, Flat Airfoil with Elastically Mounted Trailing Edge

Apte

Liburdy

Visbal

2012

42nd AIAA Fluid Dynamics Conference and Exhibit

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Direct numerical simulations were performed to study the effect of an elastically mounted trailing edge actuator on the unsteady flow over a plunging, thin airfoil at Reynolds number of 14700 based on the chord length. The goal is to investigate potential benefits of flow-induced passive actuation of the trailing edge to the lift and drag characteristics of flapping MAV wings. The trailing edge, of 30% the chord length, is hinged to the wing using a torsion spring. It may undergo flow induced rotation resulting in dynamic variations in the airfoil shape. This trailing-edge spring assembly is modeled by simple, linear, torsion spring dynamics. A small parameter space varying the spring flexibility is explored to investigate its effect on the airfoil performance. Firstly, the second-order fictitious domain based finite volume approach by Apte et al. (J. Comp. Phys. 2009) was extended to model this fluid-structure interaction problem on a fixed, Cartesian mesh. Verification studies were conducted on a canonical test case of a spring-mounted cylinder to show good predictive capability. Secondly, flow over a plunging thin flat airfoil, at reduced frequency of 5.7 (10 Hz) and 5 • angle of attack was investigated with and without the actuation of the trailing edge. It was found that, spring natural frequencies higher than the plunging frequency result in the tailing edge actuation that leads to net increase in thrust. The phase difference between the leading and trailing edge motions was found to vary based on the spring flexibility and played a critical role in governing wing performance.

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“…This is supported by the experimental work of Song et al 50 and Molki and Breuer. 51 Under these assumptions, the C l of the 2D inextensible membrane is given by…”

Section: Va Verification Against Analytical Model For Low Aoamentioning

confidence: 99%

Electro-aeromechanical modelling and feedback control of actuated membrane wings

Buoso

Palacios

2015

23rd AIAA/AHS Adaptive Structures Conference

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© 2015, by the American Institute.This paper presents a numerical investigation on the potential for unsteady aerodynamic control on integrally-actuated membrane wings made of dielectric elastomers (DEs). They combine the advantages of membrane shape adaptability, which produces increased lift and delayed stall, with the benefits of simple, lightweight but high-authority control mechanism offered by integral actuation. High-fidelity numerical models have been developed to predict their performance and include a fluid solver based on the direct numerical integration of the unsteady Navier-Stokes equations, an electromechanical constitutive material model and a non-linear three-dimensional membrane structural model. Numerical results show that harmonic actuation of 5.0 kV gives an overall increase in the aerodynamic efficiency a fixed wing configuration the wing of up to 6.0%, measured as the lift-to-drag ratio. In addition, the definition of a reduced order model based on POD modes of the complete high-fidelity system allows the synthesis of a feedback control system to obtain on-demand aerodynamic performance

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Oscillatory motions of a prestrained compliant membrane caused by fluid–membrane interaction

Cited by 32 publications

References 16 publications

Shape, lift, and vibrations of highly compliant membrane wings

Shape, lift, and vibrations of highly compliant membrane wings

Low Reynolds Number Flow Dynamics of a Thin, Flat Airfoil with Elastically Mounted Trailing Edge

Electro-aeromechanical modelling and feedback control of actuated membrane wings

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