Experimental investigations of a full model with adaptive elasto-flexible membrane wings

Pflüger, Jonathan; Breitsamter, Christian

doi:10.1016/j.cja.2020.03.037

Cited by 12 publications

(5 citation statements)

References 13 publications

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“…Before the comparison of the aerodynamic and flow field data associated to the flexible and the rigid wing, the numerical results are validated by experimental measurements and the resulting differences are explained. Therefore, the lift coefficient of the FSI simulations with a flexible wing is compared to the results of force and moment measurements of the original W/T model (Pflüger and Breitsamter, 2020). The resulting forces are made dimensionless by the dynamic pressure and the wing surface area for the experiment, and the half wing surface area for the numerics, respectively.…”

Section: Validation Of the Numerical Results By Experimental Datamentioning

confidence: 99%

Efficacy of an elasto-flexible morphing wing at high lift using fluid-structure-interaction simulations

Pflüger

Langsdorff

Breitsamter

2022

Front. Aerosp. Eng.

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The wide field of applications is the driving force behind the scientific interest in unmanned and micro air vehicles. For these aircraft, morphing wing technologies offer the possibility to adapt the aerodynamics to different flight stages. A morphing wing configuration with two elasto-flexible membrane wings is investigated numerically at a low Reynolds number of Re = 264000. The concept enables wing folding over a wide range and it allows the wing to adapt to changing aerodynamic loads. The focus is set on the benefits of the membrane in the high lift regime. Therefore, fluid-structure-interaction simulations are performed for the model equipped with a flexible and with a rigid wing. The comparison of the numerical results to data from previous experimental measurements show a good agreement. Compared with the rigid wing, the elasto-flexible membrane increases the gradient in the linear region and the maximum lift coefficient. In addition, the maximum lift coefficient is shifted to higher angles of attack. For selected wing positions and angles of attack, the aerodynamic behavior of the flexible and the rigid wing are investigated by means of the lift coefficient, the deformation of the membrane, the wall shear stresses and the wing surface pressure distribution. The deformation of the wing surface directly influences the area of flow separation at the extended wing and the separating leading-edge vortex at the folded wing. Both effects increase the generated lift of the wing with a flexible membrane.

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Section: Validation Of the Numerical Results By Experimental Datamentioning

confidence: 99%

Efficacy of an elasto-flexible morphing wing at high lift using fluid-structure-interaction simulations

Pflüger

Langsdorff

Breitsamter

2022

Front. Aerosp. Eng.

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“…The idea of morphing wings is to continuously modify aerodynamics for various flying phases [12]. The aspect ratio (AR) and sweep of the wing may be adjusted to accommodate , 01193 (2024) MATEC Web of Conferences https://doi.org/10.1051/matecconf/202439201193 392 ICMED 2024 various flight circumstances.…”

Section: Literature Reviewmentioning

confidence: 99%

Gliding Analysis of Segmented Flapping Wing

Govardhan,

Kameswara Surya Teja,

Jayahari

2024

MATEC Web Conf.

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A variety of aircraft morphing technologies have been investigated and represented by various researchers in the public domain. The morphing wing concepts involved the modification of aircraft wings during the in-flight course. Most of the technologies/concepts were based on biomimicry, where wing aerodynamic performance improved due to the change in wing shape. Here we describe a novel concept where in the flow parameters of airfoils arranged in configurations are investigated. The flow parameters are investigated using the numerical simulation tool ANSYS. A 2d flow simulation is performed using a Fluent solver to evaluate the flow configuration of the airfoils arranged in different configurations. The first configuration of airfoils is named a base, wherein the airfoils are arranged at zero angles of attack. The other two configurations are arranged by increasing the angular position of airfoils i.e., 15, 30, and 45 degrees. All these configurations are aerodynamically investigated at different sub-sonic speeds.

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“…2013; Bleischwitz, de Kat & Ganapathisubramani 2016, 2018; Bleischwitz et al. 2017; Sun & Zhang 2017; Waldman & Breuer 2017; Açıkel & Genç 2018; Genç, Açıkel & Koca 2020; Pflüger & Breitsamter 2021; Sun et al. 2022).…”

Section: Introductionunclassified

“…The existing control methods mainly include: mechanical structures; shape memory alloys; dielectric elastomer actuators and piezoelectric macro-fibre composite (MFC) actuators. Béguin, Breitsamter & Adams (2012) and Pflüger & Breitsamter (2021) combined a flexible skin with the variable sweep-angle technique to actively control the wing sweep angle through mechanical structures. The aerodynamic configuration and skin pre-strain of the wing changed with the sweep angle, and thus significantly changed the aerodynamic characteristics of the flexible wing.…”

Section: Introductionmentioning

confidence: 99%

“…It was found that the aerodynamic forces, membrane dynamics and flow evolution of membrane wings or airfoils vary greatly with the change of membrane materials (such as mass ratio, aeroelastic parameter etc.) (Tiomkin & Raveh 2019Li et al 2021), pre-strain, excess length (Song et al 2008;Rojratsirikul et al 2010), angle of attack (α), aspect ratio, Reynolds number (Re) (Gordnier 2009;Rojratsirikul et al 2011;Bleisciwitz, de Kat & Ganapathisubramani 2015;He & Wang 2020;He et al 2022), model installation and supporting methods (Hu, Tamai & Murphy 2008;Arbós-Torrent, Ganapathisubramani & Palacios 2013;Timpe et al 2013;Bleischwitz, de Kat & Ganapathisubramani 2016Bleischwitz et al 2017;Sun & Zhang 2017;Waldman & Breuer 2017;Açıkel & Genç 2018;Genç, Açıkel & Koca 2020;Pflüger & Breitsamter 2021;Sun et al 2022). By introducing the Weber number (the ratio of membrane lift to tension), Song et al (2008) and Waldman & Breuer (2017) analysed the aerodynamic and deformation characteristics of a membrane wing at various parameter conditions, trying to theoretically predict the variations of membrane camber and lift.…”

Section: Introductionmentioning

confidence: 99%

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Aerodynamics and fluid–structure interaction of an airfoil with actively controlled flexible leeward surface

Guo

et al. 2023

J. Fluid Mech.

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Piezoelectric macro-fibre composite (MFC) actuators are employed onto the flexible leeward surface of an airfoil for active control. Time-resolved aerodynamic forces, membrane deformations and flow fields are synchronously measured at low Reynolds number (Re = 6 × 104). Mean aerodynamics show that the actively controlled airfoil can achieve lift-enhancement and drag-reduction simultaneously in the angle of attack range of 10° ≤ α ≤ 14°, where the rigid airfoil encounters stall. The maximum increments of lift and lift-to-drag ratio are 27.1 % and 126 % at the reduced actuation frequency of ${f^ + } = 3.52$ . The unsteady coupling features are further analysed at α = 12°, where the maximum lift-enhancement occurs. It is newly discovered that the membrane vibrations and flow fields are locked into half of the actuation frequency when ${f^ + } > 3$ . The shift of the dominant vibration mode from bending to inclining is the reason for the novel ‘half-frequency lock-in’ phenomenon. To the fluid–structure interaction, there are three characteristic frequencies for the actively controlled airfoil: $S{t_1} = 0.5{f^ + }$ , $S{t_2} = {f^ + }$ , and $S{t_3} = 1.5{f^ + }$ . Here, St1 and its harmonics (St2, St3) are coupled with the natural frequencies of the leading-edge shear layer, resulting in the generation of multi-scale flow structures and suppression of flow separation. The lift presents comparable dominant frequencies between St1 and St3, which means the instantaneous lift is determined by the flow structures of St1 and St3. The local membrane bulge and dent affect the instantaneous swirl strength of flow structures near the maximum vibration amplitude location, which is the main reason for the variation of instantaneous lift.

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Experimental investigations of a full model with adaptive elasto-flexible membrane wings

Cited by 12 publications

References 13 publications

Efficacy of an elasto-flexible morphing wing at high lift using fluid-structure-interaction simulations

Efficacy of an elasto-flexible morphing wing at high lift using fluid-structure-interaction simulations

Gliding Analysis of Segmented Flapping Wing

Aerodynamics and fluid–structure interaction of an airfoil with actively controlled flexible leeward surface

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