A Computational Framework for Helicopter Fuselage Drag Reduction Using Vortex Generators

Boniface, Jean-Christophe

doi:10.4050/jahs.61.032002

Cited by 8 publications

(10 citation statements)

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“…The experimental activity included tests of VG arrays positioned on the helicopter back-ramp area. In particular, the four most promising sets of 2 × 8 co- and counter-rotating VGs resulting from the CFD optimisation (13) were considered for the wind-tunnel tests. The size and the pitch angle with respect to the local velocity field of the optimised VG configurations are reported in Table 1, where the chord length and the height of the VG are given with respect to the computed boundary layer displacement thickness (δ).…”

Section: Experimental Set-upmentioning

confidence: 99%

“…In particular, the latter group also investigated the shape of a fairing for blade attachments to be used together with the optimised hub cap for a further reduction of the drag due to the rotor hub. Moreover, ONERA numerically investigated the use of Vortex Generators (VGs) positioned on the fuselage back-ramp area (13) . In fact, the pronounced upsweep of the after-body shape characterising the blunt fuselages is responsible for a recirculating region at the junction with the tail boom that yields penalties on helicopter drag.…”

Section: Introductionmentioning

confidence: 99%

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Wind-tunnel tests of a heavy-class helicopter optimised for drag reduction

et al. 2016

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Wind-tunnel tests of a heavy-class helicopter model were carried out to evaluate the effectiveness of several components optimised for drag reduction by computational fluid dynamics analysis. The optimised components included different hub-cap configurations, a fairing for blade attachments and the sponsons. Moreover, the effects of vortex generators positioned on the back ramp were investigated. The optimisation effect was evaluated by comparison of the drag measurements carried out for both the original and the optimised helicopter configurations. The comprehensive experimental campaign involved the use of different measurement techniques. Indeed, pressure measurements and stereo particle image velocimetry surveys were performed to achieve a physical insight about the results of load measurements. The test activity confirms the achievement of an overall reduction of about 6% of the original model drag at cruise attitude

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Section: Experimental Set-upmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Wind-tunnel tests of a heavy-class helicopter optimised for drag reduction

et al. 2016

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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%

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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“…The supersonic VGs can also reduce flow separation near the throat [9]. A 5% drag reduction can be achieved using proper VG configurations through cumulated effects of flow reattachment [10]. However, some researchers have revealed that, although VGs are simple devices, they still generate drag [11] because stronger vortices are generated by VGs in larger dimensions, which do not necessarily lead to better flow separation control [12].…”

Section: Introductionmentioning

confidence: 99%

Suppression of the Hydrodynamic Noise Induced by the Horseshoe Vortex through Mechanical Vortex Generators

Liu

Hongxu

et al. 2019

Applied Sciences

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The hydrodynamic noise from the horseshoe vortex can greatly destroy the acoustic stealth of underwater vehicles at low frequency. We investigated the flow-induced noise suppression mechanism by mechanical vortex generators (VGs) on a SUBOFF model. Based on the numerical simulation, we calculated the flow field and the sound field of the three shapes of mechanical VGs: triangular, semi-circular, and trapezoidal. The triangular VGs with an angle of 30° to the flow direction achieved a better noise reduction. The optimum noise suppression is 8.93 dB, when the distance from the triangular VGs to the sail hull’s leading edge is 0.1c, where c is the chord length. The noise reduction mechanism is such that the mechanical VGs can destroy the formation of the horseshoe vortex at the origin and produce counter-rotation vortices to weaken its intensity. We created two steel models according to the simulation, and the experimental measurement was carried out in a gravity water tunnel. The measured results showed that the formation of the horseshoe vortex could be effectively inhibited by the triangular VGs. The results in our study can provide a new method for hydrodynamic noise suppression by flow control.

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A Computational Framework for Helicopter Fuselage Drag Reduction Using Vortex Generators

Cited by 8 publications

References 0 publications

Wind-tunnel tests of a heavy-class helicopter optimised for drag reduction

Wind-tunnel tests of a heavy-class helicopter optimised for drag reduction

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

Suppression of the Hydrodynamic Noise Induced by the Horseshoe Vortex through Mechanical Vortex Generators

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