Effect of Flap and Slat Riggings on 2-D High-Lift Aerodynamics

Balaji, R.; Bramkamp, F.; Hesse, Michael; Ballmann, J.

doi:10.2514/1.19391

Cited by 28 publications

(9 citation statements)

References 33 publications

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“…To compensate for different flight mission profiles, wing morphing is essential. The most common and conventional forms of single degree-of-freedom (DOF) morphing include airfoil [13][14][15], twist [16][17][18], sweep [19,20], span [21,22], and cant morphing [23,24].…”

Section: Aeronautical Morphing Mechanismsmentioning

confidence: 99%

Kinematic Modelling of a Panel Enclosed Mechanism

Yu¹

2021

Preprint

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This thesis presents a new method for kinematic modeling and analysis of a six degree-of-freedom parallel robot enclosed by a number of sliding panels, called panel enclosed mechanism. This type of robots has been seen in applications where mechanisms are covered by changeable surfaces, such as aircraft morphing wings made of variable geometry truss manipulators. Based on the traditional parallel robot kinematics, the proposed method is developed to model the motions of a multiple segmented telescopic rigid panels that are attached to the moving branches of the mechanism. Through this modeling and analysis, a collision detection algorithm is proposed to analyze the collisions that could occur between adjacent sliding panels during motion over the workspace of the mechanism. This algorithm will help to design a set of permissible panels used to enclose the mechanism free of collision. A number of cases are simulated to show the effectiveness of the proposed method. In addition, an extra link is added to provide an additional degree-of-freedom. Various search methods are employed to evaluate optimal orientation angles to minimize collisions of adjacent panels. Finally, the effect of increased mobility is analyzed and validated as a potential solution to reduce panel collisions.

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Section: Aeronautical Morphing Mechanismsmentioning

confidence: 99%

Kinematic Modelling of a Panel Enclosed Mechanism

Yu¹

2021

Preprint

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“…synthetic jets, plasma actuators, etc. The use of leading-edge slats [ 47 , 48 ], trailing-edge flaps [ 49 , 50 ], synthetic jet/periodic excitations [ 51 , 52 , 53 ], plasma actuators [ 54 ], vortex generators [ 55 ], and dynamically deformed leading edges [ 56 ] to accomplish the flow control has been studied.…”

Section: Introductionmentioning

confidence: 99%

Flow Control around the UAS-S45 Pitching Airfoil Using a Dynamically Morphing Leading Edge (DMLE): A Numerical Study

et al. 2023

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This paper investigates the effect of the Dynamically Morphing Leading Edge (DMLE) on the flow structure and the behavior of dynamic stall vortices around a pitching UAS-S45 airfoil with the objective of controlling the dynamic stall. An unsteady parametrization framework was developed to model the time-varying motion of the leading edge. This scheme was then integrated within the Ansys-Fluent numerical solver by developing a User-Defined-Function (UDF), with the aim to dynamically deflect the airfoil boundaries, and to control the dynamic mesh used to morph and to further adapt it. The dynamic and sliding mesh techniques were used to simulate the unsteady flow around the sinusoidally pitching UAS-S45 airfoil. While the γ − Reθ turbulence model adequately captured the flow structures of dynamic airfoils associated with leading-edge vortex formations for a wide range of Reynolds numbers, two broader studies are here considered. Firstly, (i) an oscillating airfoil with the DMLE is investigated; the pitching-oscillation motion of an airfoil and its parameters are defined, such as the droop nose amplitude (AD) and the pitch angle at which the leading-edge morphing starts (MST). The effects of the AD and the MST on the aerodynamic performance was studied, and three different amplitude cases are considered. Secondly, (ii) the DMLE of an airfoil motion at stall angles of attack was investigated. In this case, the airfoil was set at stall angles of attack rather than oscillating it. This study will provide the transient lift and drag at different deflection frequencies of 0.5 Hz, 1 Hz, 2 Hz, 5 Hz, and 10 Hz. The results showed that the lift coefficient for the airfoil increased by 20.15%, while a 16.58% delay in the dynamic stall angle was obtained for an oscillating airfoil with DMLE with AD = 0.01 and MST = 14.75°, as compared to the reference airfoil. Similarly, the lift coefficients for two other cases, where AD = 0.05 and AD = 0.0075, increased by 10.67% and 11.46%, respectively, compared to the reference airfoil. Furthermore, it was shown that the downward deflection of the leading edge increased the stall angle of attack and the nose-down pitching moment. Finally, it was concluded that the new radius of curvature of the DMLE airfoil minimized the streamwise adverse pressure gradient and prevented significant flow separation by delaying the Dynamic Stall Vortex (DSV) occurrence.

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“…The current flow control methods of the suppression of the dynamic stall of the rotor include both passive and active control methods. Passive control methods include vortex generators [10][11][12], Gurney flaps [13][14][15], fixed leading-edge slats [16,17], and fixed-droop leading edges [18]. However, these methods only have a good control effect on the suppression of the dynamic stall of the rotor under the design conditions; when the actual conditions deviate from the design conditions, the control effect is poor.…”

Section: Introductionmentioning

confidence: 99%

Study on Dynamic Stall Control of Rotor Airfoil Based on Coflow Jet

Liu

Chen

Qiu

et al. 2020

International Journal of Aerospace Engineering

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In this study, a dynamic stall control strategy, called the co-flow jet (CFJ), is applied to the rotor airfoil. The effect of the CFJ on the unsteady dynamic stall characteristics of the rotor airfoil is numerically investigated via numerical simulations of the unsteady Reynolds-averaged Navier-Stokes (URANS) equations coupled with the Spalart-Allmaras (S-A) turbulence model. The numerical methods are validated by a NACA0012 pitching airfoil case and a NACA6415 airfoil case based on the CFJ, and good agreement with experiments is found. Via the study of the typical conditions of CFJ control to suppress the dynamic stall of the OA212 rotor airfoil, it is verified that this method has a good effect on dynamic stall suppression. The diffusion and blending of the turbulent shear layer between the CFJ injection jet and the main flow excite the main flow and enhance its ability to resist the reverse pressure gradient; this suppresses the generation and development of the separation vortex, thereby enhancing the aerodynamic characteristics, improving the hysteresis effect, and increasing the system stability. On this basis, the control parameters of the CFJ are further studied, including the influences of the jet momentum coefficient and the positions and sizes of the injection and suction slots on suppressing the dynamic stall of the rotor airfoil. It is found that there is a jet momentum coefficient that optimizes the suppression effect of the dynamic stall of the rotor airfoil. Moreover, the position of the injection slot is found to have a greater effect on the dynamic stall suppression, while the size of the injection slot and the position and size of the suction slot have little effect.

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Effect of Flap and Slat Riggings on 2-D High-Lift Aerodynamics

Cited by 28 publications

References 33 publications

Kinematic Modelling of a Panel Enclosed Mechanism

Kinematic Modelling of a Panel Enclosed Mechanism

Flow Control around the UAS-S45 Pitching Airfoil Using a Dynamically Morphing Leading Edge (DMLE): A Numerical Study

Study on Dynamic Stall Control of Rotor Airfoil Based on Coflow Jet

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