Experimental investigation of the vortical activity in the close wake of a simplified military transport aircraft

Bury, Yannick; Jardin, Thierry; Klöckner, Andreas

doi:10.1007/s00348-013-1524-4

Cited by 33 publications

(16 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The vortex pair generates a strong upwash, which may interfere with airdrop missions (Bury et al 2013).…”

Section: List Of Symbols a Mmentioning

confidence: 99%

“…Epstein et al (1994) also concluded that the size and shape of the afterbody vortex was only weakly, if at all, dependent upon the Reynolds number. Bury et al (2013) investigated the near-wake flow field using crossflow measurements and discussed the effects of having open and closed ramp doors on the afterbody vortex flow field. Opening the cargo ramp resulted in the formation of an induced pair of cargo ramp vortices with opposite vorticity compared to the existing afterbody vortex pair.…”

Section: List Of Symbols a Mmentioning

confidence: 99%

See 1 more Smart Citation

Afterbody vortices of axisymmetric cylinders with a slanted base

et al. 2017

View full text Add to dashboard Cite

“…The vortex pair generates a strong upwash, which may interfere with airdrop missions (Bury et al 2013).…”

Section: List Of Symbols a Mmentioning

confidence: 99%

Section: List Of Symbols a Mmentioning

confidence: 99%

Afterbody vortices of axisymmetric cylinders with a slanted base

et al. 2017

View full text Add to dashboard Cite

“…11 for the baseline case and the blowing configuration, where xj/L = 0.2, αj = 30°, βj = 0°. The meandering amplitude is defined as: (1) where N is the number of PIV snapshots, zi and zc are the center coordinates of the instantaneous and time-averaged vortex in the spanwise direction, yi and yc are the center coordinates of the instantaneous and time-averaged vortex in the normal direction. Figure 11 demonstrates a general increase of meandering amplitude with streamwise distance up to x/L = 0.8, beyond which a decrease occurs.…”

Section: Vortex Meanderingmentioning

confidence: 99%

“…This angle is the cause of a large region of low pressure in the near-wake, resulting in the formation of a longitudinal counter-rotating vortex pair which is convected downstream. 1,2 Force measurements on geometries with an axisymmetric forebody and a slanted base have shown that the drag coefficient increases with upsweep angle for a given Reynolds number. 3,4 This evidence demonstrates why the issue is more pertinent to military transport aircraft compared to their civil counterparts.…”

Section: Introductionmentioning

confidence: 98%

Control of Afterbody Vortices by Blowing

Jackson

Wang

Gursul

2015

45th AIAA Fluid Dynamics Conference

View full text Add to dashboard Cite

An experimental study has been performed to examine the effect of blowing via a pair of jets from the upswept face of a slanted base cylinder, upon the development of the afterbody vortex flow field. Jet vortices initially interact with the shear layer separated from the upswept section. The nature of the early interactions between the jet and shear layer is highly dependent upon the blowing direction. For most blowing configurations tested, the shear layer becomes wrapped around the jet vortex. The most significant evidence of modification of the afterbody vortex pair was found when initiating a jet vortex further outboard and closer to the shear layer. The jet/vortex interactions initially cause the afterbody vortices to form further outboard, at a greater distance from the surface, and with a smaller vortex core. There is a reduction in the circulation over the first half of the afterbody length, before it recovers to baseline levels at the trailing edge. The vortex pair appears more diffuse near the trailing edge, but this is a result of increased meandering. Nomenclature am = meandering amplitude xj = streamwise jet location Aj = cross-sectional area of jet y = normal distance c = chord length of upswept face z = spanwise distance Cµ = jet momentum coefficient, ρAjUj 2 /0.5ρU∞ 2 S zj = spanwise jet location D = diameter of fuselage α = fuselage incidence angle L = length of afterbody αj = jet incidence angle r = distance from vortex center β = fuselage yaw angle Re = Reynolds number, ρU∞D/µ βj = jet yaw angle S = cross-sectional area of fuselage Γ = circulation Uj = jet velocity µ = viscosity U∞ = freestream velocity ρ = density V = crossflow velocity ω = vorticity x = streamwise distance

show abstract

“…Isocontours of instantaneous air mass fraction superimposed with out-of-plane vorticity isolines (dashed: negative, solid: positive) measured at τ = 4 ms after the complete opening of the blades (blade rotation is counterclockwise), for an opening time of 10 ms (left), 21 ms (center), and 30 ms (right). Circles and disks symbolise vortex core diameter and strength (based on λ 2 criterion[21], with a λ 2 threshold arbitrarily fixed to −1000, as this value does not impact significantly the computed vortex parameters), respectively (blue/red for negative/positive vorticity). Vortex core diameters are proportional to circle diameters and scale with figure size.…”

mentioning

confidence: 99%