Numerical Analysis of the SKYLON Spaceplane in Hypersonic Flow

Eggers, Thino; Dittrich, Robert; Varvill, Richard

doi:10.2514/6.2011-2298

“…[1][2][3][4] However, supersonic flight is usually limited to fighter aircraft because shock waves are generated. These shock waves have negative effects on the aircraft; the region behind the shock wave has high temperature and pressure, and this requires resistant materials and degrades flight efficiency.…”

Section: Introductionmentioning

confidence: 99%

Bow-shock instability induced by Helmholtz resonator-like feedback in slipstream

Ohnishi

¹

,

Sato

²

,

Kikuchi

³

et al. 2015

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Bow-shock instability has been experimentally observed in a low-γ flow. To clarify its mechanism, a parametric study was conducted with three-dimensional numerical simulations for specific heat ratio γ and Mach number M. A critical boundary of the instability was found in the γ-M parametric space. The bow shock tends to be unstable with low γ and high M, and the experimental demonstration was designed based on this result. The experiments were conducted with the ballistic range of the single-stage powder gun mode using HFC-134a of γ = 1.12 at Mach 9.6. Because the deformation of the shock front was observed in a shadowgraph image, the numerical prediction was validated to some extent. The theoretical estimation of vortex formation in a curved shock wave indicates that the generated vorticity is proportional to the density ratio across the shock front and that the critical density ratio can be predicted as ∼10. A strong slipstream from the surface edge generates noticeable acoustic waves because it can be deviated by the upstream flow. The acoustic waves emitted by synchronizing the vortex formation can propagate upstream and may trigger bow-shock instability. This effect should be emphasized in terms of unstable shock formation around an edged flat body.

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“…Figure 2 shows a typical indicial lift response to an arbitrary step change in angle of attack. Assuming a sinusoidal motion about a mean angle α 0 with an amplitude of α 1 yields αt α 0 α 1 e iωt (2) Following derivations in [7], real and imaginary parts of the force coefficient can be written as…”

Section: B Indicial Methodsmentioning

confidence: 99%

“…It is found that 3600 steps per cycle (NSPC) with 15 Newton subiterations (NWIT) are adequate for accurate unsteady responses for k b 1.13 (corresponding to assumed values of M ∞ 3.0, oscillating frequency 4 Hz, and b 130 ft [2]). The corresponding nondimensional time step size is 0.00232.…”

Section: B Demonstration For Next-generation Hypersonic Transportmentioning

confidence: 99%

“…The SSO was dynamically stable because it was rigid compared with typical transport vehicles. However, to increase the payload capacity, new concept vehicles [2] need larger length-to-width ratios than the SSO configuration. As a result, dynamic stability becomes a more important design consideration for future hypersonic vehicles compared with SSO configurations.…”

mentioning

confidence: 99%

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Dynamic Stability Analysis of Hypersonic Transport During Reentry

Guruswamy

¹

2016

AIAA Journal

2

0

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Dynamic stability analysis is performed for a typical future hypersonic transport vehicle during atmospheric flight. Unsteady aerodynamic data in the form of indicial responses are generated by solving the Navier-Stokes equations. Computations needed at multiple Mach numbers and associated angles of attack are computed in a single job by using dual-level parallel script. Validity of the indicial approach is established by comparing results with experiment and the time-integration method. Flutter boundaries associated with pitch and heave rigid-body degrees of freedom are computed. Effect of position of the mass center on flutter boundaries, which is more predominant in the transonic regime, is shown. This work advances stability analysis procedures for next-generation hypersonic vehicles. Nomenclature

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Dynamic Stability Analysis of Hypersonic Transport during Reentry

Guruswamy

¹

2016

AIAA Atmospheric Flight Mechanics Conference

0

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Dynamic stability analysis is performed for a typical future hypersonic transport vehicle during atmospheric flight. Unsteady aerodynamic data in the form of indicial responses are generated by solving the Navier-Stokes equations. Computations needed at multiple Mach numbers and associated angles of attack are computed in a single job by using dual-level parallel script. Validity of the indicial approach is established by comparing results with experiment and the time-integration method. Flutter boundaries associated with pitch and heave rigid-body degrees of freedom are computed. Effect of position of the mass center on flutter boundaries, which is more predominant in the transonic regime, is shown. This work advances stability analysis procedures for next-generation hypersonic vehicles.

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Numerical Analysis of the SKYLON Spaceplane in Hypersonic Flow

Cited by 3 publications

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Bow-shock instability induced by Helmholtz resonator-like feedback in slipstream

Bow-shock instability induced by Helmholtz resonator-like feedback in slipstream

Dynamic Stability Analysis of Hypersonic Transport During Reentry

Dynamic Stability Analysis of Hypersonic Transport during Reentry

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