Some Aerodynamic and Aerothermodynamic Considerations for Reusable Launch Vehicles

Kubota, Hirotoshi

doi:10.2514/6.2004-2428

Cited by 5 publications

(5 citation statements)

References 2 publications

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“…For their estimation, bias limit 'B' and precision limit 'P' are defined and the true value of the variable is expected to lie between respective limit intervals. The Precision limit is given as, (4) where, k is called the student k value determined from the degree of freedom which is a measure of data independence. S 2 is the unbiased estimate of population variance, defined by (5) and the mean value x is calculated as,…”

Section: Uncertainty Analysismentioning

confidence: 99%

“…Recently, the interest in the use of aerospikes for prospective space transportation applications has been renewed and caught global attention. Kubota et al [4][5] has effectively conducted research on spiked blunt bodies with aerodisks and aerospikes and concluded disks to be more effective than spikes. They also emphasized that proper selection of aerospikes holds a great potential for passive thermal protection and drag reduction.…”

Section: Introductionmentioning

confidence: 99%

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Hypersonic Flow Investigation of Aerospikes for Delta-type Lifting Body Configurations

Khurana¹,

Suzuki²

2012

AEROSPACE TECHNOLOGY JAPAN

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The increased drag and convective heating associated with flow at hypersonic speeds have a significant impact on the design of vehicles. To alienate this problem, a thorough literature review proclaims the research on using aerospikes and aerodisks as passive control devices. However, these studies have been conducted only on simple axisymmetric geometries and not on representative lifting body shapes. As a preliminary design study, the efforts were focused on analysis of using forward-facing aerospikes and its effectiveness with varying angle of attack (-10° to +10°) and spike-nose configuration, on key aerothermodynamic parameters of drag and heat reduction for prospective application to lifting body configuration, forming a delta shape with non-axisymmetric forward stagnation surface. Flow visualization was carried out using the schlieren technique. Measurements made at freestream Mach number 7 with six-component force balance system revealed a 100% increase in the Lift/Drag Ratio and no significant change in pitching moment coefficient compared to No-spike case, with aerospikes proving worthy at high angles of attack; thereby indicating their practical feasibility for eventual future applications to spacecrafts.

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Section: Uncertainty Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hypersonic Flow Investigation of Aerospikes for Delta-type Lifting Body Configurations

Khurana¹,

Suzuki²

2012

AEROSPACE TECHNOLOGY JAPAN

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“…Kubota (10) has investigated the overall characteristics of the spiked blunt body configuration at hypersonic Mach numbers. Motoyama et al (11) have experimentally analysed the aerodynamic and heat transfer characteristics of conical, hemispherical, flat-face aerospikes and hemispherical and flat-face discs attached to blunt bodies for a freestream Mach number 7, freestream Reynolds number of 4 × 10 5 /m for L/D = 0.5 and 1.0, and angle-of-attack 0° to 8°.…”

Section: Introductionmentioning

confidence: 99%

Investigation of aerodynamic coefficients at Mach 6 over conical, hemispherical and flat-face spiked body

2017

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A forward spike attached to a blunt body significantly alters its flow field characteristics and influences aerodynamic characteristics at hypersonic flow due to formation of separated flow and re-circulation region around the spiked body. An experimental investigation was performed to measure aerodynamic forces for spikes blunt bodies with a conical, hemispherical and flat-face spike at Mach 6 and at an angle-of-attack range from 0° to 8° and length-to-diameterL/Dratio of spike varies from 0.5 to 2.0, whereLis the length of the spike andDis diameter of blunt body. The shape of the leading edge of the spiked blunt body reveals different types of flow field features in the formation of a shock wave, shear layer, flow separation, re-circulation region and re-attachment shock. They are analysed with the help of schlieren pictures. The shock distance ahead of the hemisphere and the flat-face spike is compared with the analytical solution and is showing satisfactory agreement with the schlieren pictures. The influence of geometrical parameters of the spike, the shape of the spike tip and angle-of-attack on the aerodynamic coefficients are investigated by measuring aerodynamic forces in a hypersonic wind tunnel. It is found that a maximum reduction of drag of about 77% was found for hemisphere spike ofL/D= 2.0 at zero angle-of-attack. Consideration for compensation of increased pitching moment is required to stabilise the aerodynamic forces.

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“…Most of the experimental studies on spiked bodies are carried out to get effects on aerodynamic heating [3][4][5] and the surface pressure distributions [6 -8] at supersonic and hypersonic Mach numbers [9][10][11][12]. Kubota [13] has experimentally investigated the overall characteristics of the spiked blunt body configuration at hypersonic Mach numbers. Crawford [14] experimentally investigated the effects of the spike length on the nature of the flow field for a freestream mach number 6.8 and Reynolds number 0.12x10 6 -1.5x10 6 based on the cylinder diameter.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer Analysis over Disc and Hemispherical Spike Attached to Blunt-Nosed Body at Mach 6

Mehta¹

2011

17th AIAA International Space Planes and Hypersonic Systems and Technologies Conference

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Aero-spike attached to a blunt body significantly alters its flow field and influences aerodynamic drag at high speeds. The dynamic pressure in the recirculation area is highly reduced and this leads to the decrease in the aerodynamic drag. Consequently, the geometry of the aero-spike has to be simulated in order to obtain a large conical recirculation region in front of the blunt body to get beneficial drag reduction. Axisymmetric compressible NavierStokes equations are solved using a finite volume discretization in conjunction with a multistage Runge-Kutta time stepping scheme. The effect of the various types of aero-spike configurations on the reduction of aerodynamic drag is evaluated numerically at Mach 6 at a zero angle of attack. The computed density contours agree well with the schlieren pictures. Additional modification to the tip of the spike to get the different type of flow field such as formation of shock wave, separation area and reattachment point are examined flat-disk spike and hemispherical disk spike attached to the blunt nosed body. One of the critical heating areas is at the stagnation point of a blunt body, where the incoming hypersonic flow is brought to rest by a normal shock and adiabatic compression. Therefore the problem of computing the heat transfer rate near the stagnation point needs a solution of the entire flow field from the shock to the spike body. The bow shock distance ahead of the hemispherical and flat-disc is compared with the analytical solution and an agreement found between them. The influence of the shock wave generated from the spike is used to analysis the pressure distribution, the coefficient of skin friction and the wall heat flux facing the spike surface to the flow direction. The numerical analysis gives complete flow field information over the spike surface including the stand-off distance shock, sonic line, and velocity gradient along the surface of the spike. Nomenclaturelength of the spike M = Mach number q = wall heat flux Pr = Prandtl number p = pressure pa = ambient pressure s = distance along the surface of the spike R, S = vicous flux t = time u, v = velocity components 2 W = conservative vector γ = ratio of specific heats µ = viscosity ρ = density σ = normall stress µ = shear stress Subscripts w = wall ∞ = freestream condition

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Some Aerodynamic and Aerothermodynamic Considerations for Reusable Launch Vehicles

Cited by 5 publications

References 2 publications

Hypersonic Flow Investigation of Aerospikes for Delta-type Lifting Body Configurations

Hypersonic Flow Investigation of Aerospikes for Delta-type Lifting Body Configurations

Investigation of aerodynamic coefficients at Mach 6 over conical, hemispherical and flat-face spiked body

Heat Transfer Analysis over Disc and Hemispherical Spike Attached to Blunt-Nosed Body at Mach 6

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