Flowfield Around Spike-Tipped Bodies for High Attack Angles at Mach 4.5

Gnemmi, Patrick; Srulijes, J.; Roussel, K.; Runne, K.

doi:10.2514/2.6910

Cited by 61 publications

(30 citation statements)

References 11 publications

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“…The flat aerodisk was found to produce the least drag. Kurbatskii and Montanari [18] numerically investigated the same models previously examined in [2,17].…”

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confidence: 96%

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Drag Reduction Using Aerodisks for Hypersonic Hemispherical Bodies

Ahmed

Qin

2010

Journal of Spacecraft and Rockets

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The main challenge facing the designers of hypersonic vehicles is the significantly high levels of pressure drag and aerodynamic heating. Although blunt noses are preferred for better heat distribution, they introduce substantial drag to the vehicle. Spikes and aerodisks proved to be efficient drag and heating reduction devices. However, for some flow conditions and model designs, the flow around spiked bodies can be unstable, which deteriorates their effectiveness. In the present study, a numerical investigation was conducted on a hemispherical body equipped with a spike of variable length and a hemispherical aerodisk of variable size in laminar hypersonic freestream conditions. A mechanism is proposed to explain the drag reduction and the cause of flow instability based on the shape of an effective body. In addition, the dependence of drag reduction on the spike's detailed design was investigated. For the models investigated in this work, an optimum aerodisk size produced the minimum drag and this optimum size was found to be inversely proportional to the spike length. Nomenclature b = arc length of half a semicircle, m C D = drag coefficient D = main body diameter, m d = aerodisk diameter, m L = spike length, m M = Mach number P = pressure, Pa q = dynamic pressure, Pa Re = Reynolds number S = surface area, m 2 s = distance along the surface, m T = temperature, K V = flow velocity, m=s = inclination of separation shock wave = specific heat ratio = efficiency of compression = inclination of the dividing streamline = dynamic viscosity, kg=m s = density, kg=m 3 Subscripts d = value inside the recirculation zone inf, 1 = freestream value o = total, stagnation value p = peak value r = reattachment value ref, = reference value

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“…The flat aerodisk was found to produce the least drag. Kurbatskii and Montanari [18] numerically investigated the same models previously examined in [2,17].…”

mentioning

confidence: 96%

“…Their experiments were reproduced numerically by Asif et al [15]. Gnemmi et al [17] investigated three different aerodisk designs, namely, flat, spherical, and biconical disks, used with a spike of a fixed length (L=D 1) and a hemisphere cylindrical model. The investigation involved experimental measurements along with numerical simulations.…”

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confidence: 99%

Drag Reduction Using Aerodisks for Hypersonic Hemispherical Bodies

Ahmed

Qin

2010

Journal of Spacecraft and Rockets

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“…From the outcome, they found that the rounded tip aerospike is better in drag reduction than the pointed tip one. Later their consequences were duplicated numerically by Asif et al [7]. Gnemmi et al [8] proved that the flat aerodisk can produce the minimum drag, comparing with spherical and biconical disks under the same aerospike length.…”

Section: Introductionmentioning

confidence: 95%

Drag Reduction Optimization for Hypersonic Blunt Body with Aerospikes

Wan¹,

Cm²

2017

J Aeronaut Aerospace Eng

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Pressure drag and aeroheating stirred by the shock wave is the main challenge of hypersonic flight, and blunt body is always the principle configuration at hypersonic flow regime for heat distribution, but it would induce substantial drag. Therefore, both aerospikes and aerodisks can be efficiently utilized as a mean for drag reduction. In this work, we investigate the effect of different geometric shapes of aerospikes with various disk gap widths on drag reduction. Accordingly, a series of numerical simulation work was implemented to find the behaviour as to hypersonic flow over aerospiked blunt bodies. Moreover, the drag reduction efficiency of spiked blunt bodies would be optimized via the Kriging method. For the models we studied, we found that the drag on the spiked blunt bodies is much lower than the spike off one. The drag reduction efficiency especially would be predominated by the scale of recirculation zone, which increases as both the spike length and the gap size of aerodisk increase. Hence, the performance of drag diminution will depend on the design parameters such as main body configurations, aerospike length, and tip geometric shapes.

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“…Even for small α, the e¨ectiveness decreases considerably. The bene¦cial e¨ect completely disappears between α = 15 • and 20 • [2,22]. This is due to the transformation of the favorable symmetric shock system (see Fig.…”

Section: Introductionmentioning

confidence: 96%

Wave drag reduction with a self-aligning aerodisk on a missile configuration

Schnepf

Wysocki

Schülein

2017

Progress in Flight Physics

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A self-aligning aerodisk to reduce the wave drag on a pitching missile is numerically investigated. The motion and the Mach number were chosen to match a maneuver §ight of an actual missile: pitching frequency f = 7.5 Hz, Mach number M = 2.2, and range of angle of attack 0 • < α < 21 • . The self-alignment was realized with a coupling of the §ow solver with a 6DoF (6 degrees of freedom) tool. In the entire range of angle of attack, the drag could be reduced with the self-aligning aerodisk. A comparison with experimental data showed in parts a quite good agreement in the aerodynamic coe©cients, in the shock structure, and in the alignment of the aerodisk.

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Flowfield Around Spike-Tipped Bodies for High Attack Angles at Mach 4.5

Cited by 61 publications

References 11 publications

Drag Reduction Using Aerodisks for Hypersonic Hemispherical Bodies

Drag Reduction Using Aerodisks for Hypersonic Hemispherical Bodies

Drag Reduction Optimization for Hypersonic Blunt Body with Aerospikes

Wave drag reduction with a self-aligning aerodisk on a missile configuration

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