Experimental investigation of a helicopter rotor with Gurney flaps

Gibertini, G.; Zanotti, Alex; Droandi, Giovanni; Auteri, Franco; Crosta, G

doi:10.1017/aer.2016.120

Cited by 5 publications

(3 citation statements)

References 31 publications

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“…Several passive and active methodologies have been investigated to control the transient aeroelastic response of shipboard rotors. The active Gurney Flap (GF) is a simple and effective high lift enhancement device, and has been used to control rotor vibration and improve rotor performance in steady flight [16][17][18][19][20]. However, it has not yet been explored in controlling the transient response.…”

Section: Introductionmentioning

confidence: 99%

Transient Aeroelastic Response Control of Shipboard Rotors During Engagements by Gurney Flaps

Han

Barakos

2019

Journal of Aircraft

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Active Gurney flaps are explored to reduce the transient aeroelastic response of shipboard rotors. A beam model based on the generalized force formulation is used to represent the rotor blade. Using this model, predictions of the transient response of a teetering model rotor were in good agreement with test data. An active Gurney flap with a prescribed harmonic motion was then deployed. The results indicate that a suitable actuation schedule of the Gurney flap can lead to a significant reduction of the blade tip deflection. Excessively large amplitudes of the Gurney flap actuation were found not to be beneficial, since these may lead to excessively large blade tip deflection at certain instants. A Gurney flap located at the blade tip achieved the best performance. The control strategy of the motion of the active Gurney flap can be further optimized, for even larger benefits.

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Section: Introductionmentioning

confidence: 99%

Transient Aeroelastic Response Control of Shipboard Rotors During Engagements by Gurney Flaps

Han

Barakos

2019

Journal of Aircraft

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“…GF has been extended to rotors with blade sections of various airfoils. Gibertini et al 21 investigated the performance of GFs on a helicopter rotor model in hovering and the experiment results showed an apparent benefit produced by GFs in terms of rotor performance with respect to the clean blade configuration. Ismail and Vijayaraghavan 22 utilized an optimized combination of GF and semi-circular inward dimple on a vertical axis wind turbine.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical study on the performance of an axial fan with a Gurney flap

Chen

Xie

et al. 2018

Advances in Mechanical Engineering

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Gurney flap is a miniature lift-enhancement device installed at the airfoil trailing edge and has been successfully applied to fixed wing aircraft and low-speed horizontal wind turbines. In this article, Gurney flap is extended to increase pressure output of a diffusive cascade flow in rotating turbomachinery, which is complicated for its three dimensionalities and diffusive separation characteristics. Wind tunnel tests and computational fluid dynamic simulations were accomplished on an axial fan profiled with an NACA 65-(12)10 airfoil to investigate the effects of Gurney flap on the performance of a high solidity. We present the detailed flow features of the fan with and without Gurney flap after validating the simulation results with the experimental datum. The experimental results show positive Gurney flap effects on fan's pressure rise and flow rate improvement. However, negative Gurney flap effects on fan's efficiency are more evident than Gurney flap on isolated airfoils. Detailed flow field analysis from computational fluid dynamic computation reveals that the increased airfoil pressure loading along the fan blade chord strengthens the tip leakage flow, which induces more tip second flow losses than in the baseline fan. In addition to the positive lift enhancement, the net Gurney flap effect in diffusion cascade is influenced by the three-dimensional flow structure.

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“…On the other hand, the second method controls flow by adding energy or momentum to the flow in a regulated manner. Actuators are at the heart of active flow control implementation and several concepts were introduced in literature such as Spar85Def10 concept [24], Active Camber Deformation [25], Variable Droop Leading Edge (VDLE) [26,27], Nose-Droop Concept [28], Static Extended Trailing Edge (SETE) [29], Trailing-Edge Flap (TEF) [30], and Gurney Flap (GF) [31,32]. The important step before modifying the standard blade design with the installation of the passive or active devices on the helicopter blade is to determine the exact location of flow separation region along the retreating side [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic prediction of helicopter rotor in forward flight using blade element theory

Yaakub¹,

Wahab²,

Abdullah³

et al. 2017

J. MECH. ENG. SCI.

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In this study, the helicopter blade in forward-flight condition was investigated. The blade element theory (BET) was used throughout this analysis to investigate the angle of attack variations at the blade cross sections, lift distribution along the blade and effects of increasing helicopter speed. Prouty's helicopter data was used to validate the analysis results. In this analysis, the helicopter blade was divided into 50 equally spaced elements and the azimuth ψ was set at 7.2° for each movement of the blade. The helicopter speed of 80 m/s was considered. The analysis revealed that the computation results were in good agreement with Prouty's diagram. Furthermore, it was also evident that in the case of a helicopter in forward-flight condition, the blade at retreating side was generally at low angle of attack and experienced low lift, in contrast to the blade at advancing side. The increment of the helicopter speed affected the lift distribution along the blade. The reverse flow area was widened two times from that given by the original Prouty's diagram. In addition, it was proven that each helicopter has its own speed limit called velocity never exceed (VNE). It was also shown that BET is important in conducting the analysis to modify the helicopter blade design for the aerodynamic characteristics' improvement as well as stability and general performance enhancement for the helicopter.

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Experimental investigation of a helicopter rotor with Gurney flaps

Cited by 5 publications

References 31 publications

Transient Aeroelastic Response Control of Shipboard Rotors During Engagements by Gurney Flaps

Transient Aeroelastic Response Control of Shipboard Rotors During Engagements by Gurney Flaps

Experimental and numerical study on the performance of an axial fan with a Gurney flap

Aerodynamic prediction of helicopter rotor in forward flight using blade element theory

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