Helicopter drag reduction by vortex generators

Gibertini, G.; Boniface, Jean Christophe; Zanotti, Alex; Droandi, Giovanni; Auteri, Franco; Gaveriaux, Robert; Pape, Arnaud Le

doi:10.1016/j.ast.2015.10.004

Cited by 23 publications

(10 citation statements)

References 18 publications

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“…However, it should be highlighted that the effectiveness of micro-VGs is highly sensitive toward the exact implementation location and may not be entirely suitable in applications that involve complex flow behaviors. 6,7 Vortex generators may also possess geometries that take after rectangular, triangular, wishbone, and wedge configurations, 5 among others, which work at different performance levels that depend on the exact applications and flow conditions. In particular, for subsonic flows, which most aerodynamic applications are associated with, it had been reported that the divergent vane-type VGs have the highest efficiency in terms of flow separation and overall drag reductions.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, for subsonic flows, which most aerodynamic applications are associated with, it had been reported that the divergent vane-type VGs have the highest efficiency in terms of flow separation and overall drag reductions. 7 In recent years, most studies have aimed to enhance thermal performance by means of VGs. 8 It had been found that VGs helped in improving the heat transfer in a rectangular channel, but it also increased the friction factor depending on the configurations.…”

Section: Introductionmentioning

confidence: 99%

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Flow behavior of skewed vortex generators on a backward-facing ramp

Cheawchan

Yan

Teo

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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The impact of skewness angle on the effectiveness of vortex generators (VGs) and the behavior of streamwise vortices on flow separation behind a backward-facing ramp (BFR) with a sharp transition were experimentally investigated using surface oil flow visualizations, planar and stereoscopic particle image velocimetry measurements. Counter/corotating streamwise vortices were generated by a set of boundary layer-type rectangular VG located upstream of the BFR that comprised a flat- and 30-inclined sections with different skewness angles of 10°, 20°, and 30°. Local Reynolds number based on the VG location was Rex ≈ 3 × 106. Results show that the reattachment length was reduced by ∼45% when the VG was located five times its height ahead of the transition. Additionally, the behavior of the vortex core generated by the left vane displayed strong dependence on the skewness angle, whereby its vorticity magnitude and vortex instability increase with the skewness angle. Circulation magnitude and vortex radius of the left vortex core are also observed to be physically larger and less stable. In contrast, the vortex core produced by the right vane displays opposite behavior as the skewness angle increases. Lastly, the vortex core location is observed to fluctuate more in the vertical direction than horizontal direction.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Flow behavior of skewed vortex generators on a backward-facing ramp

Cheawchan

Yan

Teo

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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“…Most of the times, engineers are looking for small changes in geometry and structure to improve an already good design. Past and recent studies (for isolated fuselages and full helicopter models) show that a significant contributor to the total drag of the helicopter fuselage is suction at its rear due to aft-facing surfaces used for ramps and rear-access [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. This is the reason for streamlined helicopter fuselage shapes.…”

Section: Introductionmentioning

confidence: 99%

“…This can be achieved in many ways including active flow control by flow suction and blowing [4], passive flow control using devices like vortex generators [5,16], and shape optimization [6].…”

mentioning

confidence: 99%

Aerodynamic optimization of helicopter rear fuselage

Batrakov

Kusyumov

Mikhaǐlov

et al. 2018

Aerospace Science and Technology

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An optimization process for the rear helicopter fuselage part is presented using Genetic Algorithms and Kriging surrogate models. Shape parameterization is carried out with the super ellipse technique employed for the well-known ROBIN fuselage. The simulations were based on the RANS equations solved using the HMB CFD code. It is shown that a decrease of fuselage drag around 2.5% is possible without compromising the structure and the functionality of the design. Combined with an optimization of the helicopter skids, benefits of up to 4.6% were possible. The demonstrated method can be applied to fuselages of any shape during the initial design phase.

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“…Pearcey, 1961 andSchubauer andSpangenberg, 1960), nowadays, the research on this topic offers new possibilities for many application fields. Concerning rotating wings, one can mention the following developments: tilt rotors whose thick and highly loaded wings are affected by early onset of buffet and separation from the work by Bevan et al (2015Bevan et al ( , 2016) via a computational fluid dynamics (CFD) investigation with OpenFOAM; and a heavy-class helicopter fuselage model, as in the work by Gibertini et al (2015), where a 5% drag reduction is reported by means of a validated numerical layout. As for marine applications in the work by Brandner and Walker (2003), an experimental study on the relation between the performance of VGs under different cavitation numbers is reported.…”

Section: Introductionmentioning

confidence: 99%

An extension of a strong viscous–inviscid coupling method for modeling the effects of vortex generators

et al. 2018

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The aim of this work is to provide insights into the advantages and the limitations of the extension of a strong viscous-inviscid interactive code for modeling the effects of vortex generators, with focus on the calibration and validation for wind turbine airfoils. The proposed methodology relies on the approach proposed by other authors in the past and introduces an alternative formulation for the lag dissipation within the integral boundary-layer equations whose effects on the numerical prediction are evaluated. Besides the verification of the aeronautical test cases, particular attention is devoted to the validation of the results for several airfoils commonly used in wind turbine design. A blind test for airfoils from an industrial test case is conducted as well. Results show that the maximum lift coefficient can be well predicted by the present implementation, whereas the angle of maximum lift is a little higher than in wind tunnel measurements. Apart from that, the drag coefficients of airfoils with vortex generators cannot be predicted by the current implementation, but it is expected that the maximum lift and the stall angle of attack are more important in the design phase, since they determine power, loads, and noise.

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Helicopter drag reduction by vortex generators

Cited by 23 publications

References 18 publications

Flow behavior of skewed vortex generators on a backward-facing ramp

Flow behavior of skewed vortex generators on a backward-facing ramp

Aerodynamic optimization of helicopter rear fuselage

An extension of a strong viscous–inviscid coupling method for modeling the effects of vortex generators

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