Towards the Investigation of Unsteady Spoiler Aerodynamics

Geisbauer, Sven; Löser, Thomas

doi:10.2514/6.2017-4229

Cited by 12 publications

(9 citation statements)

References 19 publications

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“…However, depending on the spoiler geometry and the onflow conditions, the flow might reattach before reaching the trailing edge. As published in [30], it was observed in the reference experiment that the flow reattaches for ≤ 10°and < 5°. The smallest spoiler deflection angle investigated in the validation, however, was already at = 10°.…”

Section: Influence Of Time-accurate Simulationssupporting

confidence: 52%

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Numerical Simulation and Validation of Aerodynamics of Static and Dynamic Spoilers

Geisbauer

2021

Journal of Aircraft

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Spoilers play a vital role in the flight control systems of modern transport aircraft. Due to their efficiency and fast deflection rates they are widely used to assist in roll control or for gust load alleviation purposes. Simulating the aerodynamic behavior of spoilers still is a challenging task as deflecting a spoiler always induces flow separation. The work presented in this paper therefore focused on extending the application range of DLR's in-house flow solver TAU by verifying and validating it for spoiler applications. In a first step, the work focused on steady and unsteady simulations of static and dynamic spoiler deflections in the low-speed regime. It was shown that the chosen numerical approach is well-suited to reproduce the surface pressure distribution for static spoiler deflections of up to 50°. Above that, the simulated transient aerodynamic response was found to be in good agreement with experimental data for a variety of deflection times and deflection angles.

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Section: Influence Of Time-accurate Simulationssupporting

confidence: 52%

“…Hence, corrections of any blockage effects were not applied and uncorrected wind tunnel data were used to validate the TAU code. Further details on the experimental setup, the instrumentation and the measured data were published by the author in [30].…”

Section: B Accuracy Considerationsmentioning

confidence: 99%

Numerical Simulation and Validation of Aerodynamics of Static and Dynamic Spoilers

Geisbauer

2021

Journal of Aircraft

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“…ailerons and spoilers on the wing) or even direct-lift control (DLC). Spoilers can be used to reduce loads but not to increase them, at least not in the steady case or with regular deflection speed [13]. The use of spoilers for ride control is therefore more restricted than DLC, even if spoiler deflections with the correct timing can improve the ride quality.…”

Section: Feedforward Load Alleviation Controllermentioning

confidence: 99%

“…The transformation described in Eq. (13) and illustrated in figure 6 maps any quantity to a non-negative real number and the transformation parameters b l , g l , g h , b h have to be chosen according to the following fuzzy-like description of the objective goal in terms of "bad" and "good":…”

Section: Criteria Formulationmentioning

confidence: 99%

Gust load alleviation for a long-range aircraft with and without anticipation

Fezans¹,

Joos²,

Deiler³

2019

CEAS Aeronaut J

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This paper presents an overview of the DLR activities on active load alleviation in the CleanSky Smart Fixed Wing Aircraft project. The investigations followed two main research directions: the multi-objective, multimodel, structured controller design for the feedback load alleviation part and the use of Doppler LIDAR technologies for gust/turbulence anticipation. On this latter topic, the prior work made in the AWIATOR European FP6 project constituted a reference in terms of demonstrations and the objective was not to repeat these previous investigations with a real sensor in flight test but to develop new ideas for the exploitation of the Doppler LIDAR measurements for gust alleviation purposes. Very fruitful exchanges between industry partners and research organizations took place during this project and all the work presented in this paper has been made using a generic long-range benchmark provided by Airbus on the basis of the XRF-1 model.

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“…An active GLA system based on conventional sensors for gust detection and existing control surfaces for actuation is not capable of counteracting the dynamic loads caused by all relevant gust lengths due to the limited slew rates. The required faster actuation speeds to compensate all 1-cos gusts (Geisbauer and Löser 2017) are difficult to reach due to the control surface inertia and onset of fatigue problems at highly dynamic actuation (Hönlinger et al 1994). Even considering that the shorter 1-cos gusts may not be responsible for the peak structural loads (Xu 2012), any gains in actuation speed will greatly benefit overall performance of a full GLA system, which experiences time delays due to the employed gust sensing and controller.…”

Section: Introductionmentioning

confidence: 99%

Experimental load modification on a dual-slot circulation control airfoil

2022

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Active load alleviation can substantially contribute to decrease structural weight and emissions of future transport aircraft by limiting peak aerodynamic loads that the aircraft experiences during flight. Fluidic actuators, as part of active load alleviation systems, have the potential for faster and more complete gust load reduction. The performance of a dual slot circulation control airfoil for gust load alleviation is investigated experimentally on a supercritical airfoil model. The tests are conducted in a low-speed wind tunnel at a chord-based Reynolds number of $${\text{Re}}={\text{1.5}}\cdot {\text{10}}^{{\text{6}}}$$ Re = 1.5 · 10 6 and $${\it{M}}_{{\infty }}={\text {0.14}}$$ M ∞ = 0.14 . The model features an elliptical Coandă geometry integrated into the airfoil’s trailing edge to minimize cruise performance penalty, while still allowing for substantial load reduction. Blowing from a single slot, as well as simultaneously from pressure and suction side slots is tested over a range of blowing rates to assess the impact on load modification. Both steady and impulsive activation performance are evaluated based on surface pressure, integral load, and flow field measurements around the Coandă geometry. High control authority is found for upper and lower single slot blowing, with peak changes in lift coefficient of about $$\pm\,{0.33}$$ ± 0.33 and lift-to-equivalent-drag ratio change of up to 100. Similar peak lift changes and reduced equivalent drag are obtained by adding marginal ($$< 14\%$$ < 14 % of total) blowing from the opposite slot, which also reduces pitching moment changes for primary upper and marginal lower blowing. Impulsive jet activation exhibits load control authority comparable to steady actuation and sufficiently short onset times to counteract all gusts defined by certification documentation.

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Towards the Investigation of Unsteady Spoiler Aerodynamics

Cited by 12 publications

References 19 publications

Numerical Simulation and Validation of Aerodynamics of Static and Dynamic Spoilers

Numerical Simulation and Validation of Aerodynamics of Static and Dynamic Spoilers

Gust load alleviation for a long-range aircraft with and without anticipation

Experimental load modification on a dual-slot circulation control airfoil

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