Computational aeroelastic analysis of a hovering W3 Sokol blade with gurney flap

Pastrikakis, Vasileios; Steijl, R.; Barakos, George N.; Małecki, J.

doi:10.1016/j.jfluidstructs.2014.06.014

Cited by 16 publications

(12 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5 Among these studies, the interest about the effects of a Gurney flap 6 on rotor blades 7 has recently grown, as demonstrated by the several works about the study of the potential effect of an active deployable Gurney flap (see, for instance, Refs. [8][9][10]. Both experimental and numerical activities agree about the fact that the lift enhancement mechanism of a Gurney flap can be useful to improve the blade performance.…”

Section: Introductionsupporting

confidence: 52%

“…11,12 In fact, numerical studies report that benefits for rotorcraft performance can be obtained by the use of an active Gurney flap deployed on the retreating side of rotor disk and retracted on the advancing side. 8,10 The considerations about Gurney flap control sustained by the numerical results are confirmed by wind tunnel tests carried out on a oscillating blade section model equipped with a fixed Gurney flap at the airfoil trailing edge. 13 Nevertheless, the integration of an active Gurney flap on a rotor blade represents a very challenging and costly activity, primarily due to the very severe requirement to stow the deployable device together with the required actuation mechanism inside the airfoil at the blade trailing edge.…”

Section: Introductionmentioning

confidence: 59%

See 1 more Smart Citation

Experimental investigation of a trailing edge L-shaped tab on a pitching airfoil in deep dynamic stall conditions

Zanotti

Grassi

Gibertini

2013

Proceedings of the Institution of Mechanical Engineers, Part G:

View full text Add to dashboard Cite

An L-shaped tab was tested at the trailing edge of an oscillating airfoil to evaluate its effects on blades aerodynamic performance. The tests were conducted on a NACA 23012 pitching airfoil in deep dynamic stall conditions with the L-shaped tab fixed in two different positions. When deployed the tab is attached to the airfoil upper surface so that the end prong protrudes at the airfoil trailing edge. In retracted position the tab features an angle of 9.1 with the airfoil upper surface, since its prong tip touches the airfoil trailing edge. The airloads time histories during a pitching cycle were evaluated by pressure measurements carried out on the airfoil midspan contour. The phase-averaged flow field at the trailing edge region was investigated by means of particle image velocimetry to evaluate the detailed flow physics involved in the use of the device. The experimental results indicate that the use of such a pivoting L-shaped tab can introduce similar effects to those that can be obtained by the use of an active Gurney flap. Thus, the L-shaped tab can be considered an attractive device due to its easier integration on helicopter blades.

show abstract

Section: Introductionsupporting

confidence: 52%

Section: Introductionmentioning

confidence: 59%

Experimental investigation of a trailing edge L-shaped tab on a pitching airfoil in deep dynamic stall conditions

Zanotti

Grassi

Gibertini

2013

Proceedings of the Institution of Mechanical Engineers, Part G:

View full text Add to dashboard Cite

show abstract

“…To conclude, few complete studies concerning Gurney flap implementation on helicopter rotors were found in the literature. All of them investigated the effect of Gurneys on BVI and/or vibration reduction in forward flight, while Pastrikakis et al (23) demonstrated the potential effect of Gurney flaps on a hovering rotor. Although there is strong indication from 2D calculations of potential performance enhancement, the question still remains whether there is a practical forward flight benefit to be achieved.…”

Section: Gurney Flapsmentioning

confidence: 99%

“…Earlier work (23) demonstrated the potential effect of a Gurney flap on the performance of the W3-Sokol rotor blade in hover. A rigid blade was first considered and the calculations were conducted at several thrust settings.…”

Section: Hover Flightmentioning

confidence: 99%

Effect of active Gurney flaps on overall helicopter flight envelope

2016

Self Cite

View full text Add to dashboard Cite

This paper presents a study of the W3-Sokol main rotor equipped with Gurney flaps.The effect of the a active Gurney is tested at low and high forward flight speeds to draw conclusions about the potential enhancement of the rotorcraft performance for the whole flight envelope. The effect of the flap on the trimming and handling of a full helicopter is also investigated. Fluid and structure dynamics were coupled in all cases, and the rotor was trimmed at different thrust coefficients. The Gurney proved to be efficient at medium to high advance ratios, where the power requirements of the rotor were decreased by up to 3.3%. However, the 1/rev actuation of the flap might be an issue for the trimming and handling of the helicopter. The current study builds on the idea that any active mechanism operating on a rotor could alter the dynamics and the handling of the helicopter. A closed loop actuation of the Gurney flap was put forward based on a pressure divergence criterion, and it led to further enhancement of the aerodynamic performance. Next, a generic light utility helicopter was built using 2D aerodynamics of the main aerofoil section of the W3 Sokol blade along with a robust controller, and the response of the rotorcraft to control inputs was tested. This analysis proved that the 1/Rev actuation of the Gurney did not alter the handling qualities of the helicopter, and as a result it can be implemented as a flow control mechanism for aerodynamic enhancement and retreating blade stall alleviation. * Ph.D, email: vpastrikakis@gmail.com † Senior lecturer, email: Rene.Steijl@glasgow.ac.uk ‡ Professor, email: George.Barakos@glasgow.ac.uk, Corresponding author. of 42The Aeronautical Journal The Aeronautical Journal

show abstract

“…Pastrikakis et al investigated the potential effect of a GF on the performance of W3 Sokol blade in hover and forward flight [15,16]. The results showed an increase in the aerodynamic performance by GFs, especially for high thrust conditions.…”

Section: Introductionmentioning

confidence: 99%

Performance improvement of variable speed rotors by Gurney flaps

Han

Dong

Barakos

2018

Aerospace Science and Technology

View full text Add to dashboard Cite

Gurney flaps are used for improving the performance of variable speed rotors. An analytical model able to predict helicopter rotor power is first presented, and the flight data of the UH-60A helicopter is used for validation. The predictions of the rotor power are in good agreement with the flight test data, justifying the use of this tool in analyzing helicopter performance. A fixed Gurney flap can enhance the performance of variable speed rotors and expand the corresponding flight envelop, especially near stall and high speed flight. A retractable Gurney flap at 1/rev yields more power savings than a fixed Gurney flap or a retractable one with a higher harmonic prescribed motion. At a speed of 200km/h, the retractable Gurney flap, actuated at 1/rev, can obtain 3.22% more power reduction at a rotor speed of 85% nominal rotor speed, and this value is 8.37% at a speed of 220km/h. The height corresponding to the minimum power increases slowly in low to medium speed flight, and increases dramatically in high speed flight. With increasing takeoff weight (i.e. rotor thrust), the retractable Gurney flap at 1/rev can obtain more rotor power savings.

show abstract

Computational aeroelastic analysis of a hovering W3 Sokol blade with gurney flap

Cited by 16 publications

References 33 publications

Experimental investigation of a trailing edge L-shaped tab on a pitching airfoil in deep dynamic stall conditions

Experimental investigation of a trailing edge L-shaped tab on a pitching airfoil in deep dynamic stall conditions

Effect of active Gurney flaps on overall helicopter flight envelope

Performance improvement of variable speed rotors by Gurney flaps

Contact Info

Product

Resources

About