Boundary layer transition on supersonic cones in an aeroballistic range

Potter, Jan

doi:10.2514/6.1974-132

Cited by 8 publications

(6 citation statements)

References 7 publications

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“…Previous experiments 20 and the stability calculations 22 showed that the transition Reynolds number for a blunt cone at a Mach number of 8, with nose Reynolds numbers of 30,000, increased by a factor of 1.7~2.0 compared to a sharp cone. Potter 33 found from a series of aeroballistics range experiments on nominally sharp cones that the transition Reynolds number increases with the free stream unit Reynolds number as a power of 0.63. A line with the slope of 0.60 is included in Fig.…”

Section: Figures 25(a) and (B)mentioning

confidence: 99%

“…The effects of nose tip bluntness on the stability and transition of hypersonic boundary layers have been investigated experimentally and numerically by many researchers [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] . The experiments showed that nose bluntness had a stabilizing effect upon the boundary layer and transition occurred further downstream compared to that for the sharp nose cases.…”

Section: Introductionmentioning

confidence: 99%

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Receptivity of Hypersonic Boundary Layers to Acoustic and Vortical Disturbances (Invited)

Balakumar

2015

45th AIAA Fluid Dynamics Conference

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Boundary-layer receptivity to two-dimensional acoustic and vortical disturbances for hypersonic flows over two-dimensional and axi-symmetric geometries were numerically investigated. The role of bluntness, wall cooling, and pressure gradients on the receptivity and stability were analyzed and compared with the sharp nose cases. It was found that for flows over sharp nose geometries in adiabatic wall conditions the instability waves are generated in the leading-edge region and that the boundary layer is much more receptive to slow acoustic waves as compared to the fast waves. The computations confirmed the stabilizing effect of nose bluntness and the role of the entropy layer in the delay of boundarylayer transition. The receptivity coefficients in flows over blunt bodies are orders of magnitude smaller than that for the sharp cone cases. Wall cooling stabilizes the first mode strongly and destabilizes the second mode. However, the receptivity coefficients are also much smaller compared to the adiabatic case. The adverse pressure gradients increased the unstable second mode regions. Nomenclaturea = speed of sound C recpt = receptivity coefficient c v = specific heat E = total energy e = internal energy F = flux vector in the x-direction, non-dimensional frequency f = frequency in Hz G = flux vector in the r-direction k = thermal conductivity M = Mach number N = N factor Pr = Prandtl number p = pressure p s = surface pressure Q = conserved flow variables vector R = gas constant Re = Reynolds number, per meter Re s = Reynolds number based on the distance s, per meter r = radial coordinate r 0 = nose radius S = source term s = distance along the surface T = temperature t = time U = mean axial velocity u = axial velocity 1 Research Scientist, AIAA Associate Fellow Downloaded by CARLETON UNIVERSITY LIBRARY on July 17, 2015 | http://arc.aiaa.org | American Institute of Aeronautics and Astronautics 2 V = radial velocity X = axial coordinate x 0 = reference x location α = wavenumber in the x-direction η = curvilinear coordinate in the radial direction, boundary-layer similarity coordinate δ = boundary layer thickness µ = viscosity ξ = curvilinear coordinate in the axial direction ρ = density ω = frequency in radian Subscripts ac = acoustic e = boundary-layer edge conditions max = maximum n = normal to the surface, neutral point ∞ = freestream quantities

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Section: Figures 25(a) and (B)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Receptivity of Hypersonic Boundary Layers to Acoustic and Vortical Disturbances (Invited)

Balakumar

2015

45th AIAA Fluid Dynamics Conference

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“…The transition delay trend observed on Re sB, e in figure 17a while increasing the free-stream unit Reynolds number is attributed to variations of free-stream noise levels as commonly reported in the literature. [50][51][52][53] Figure 17b illustrates the strong stabilizing effect of nosetip bluntness on the boundary layer. With a nosetip radius of 4.75 mm, an essentially laminar flow exists all along the cone with only a slight departure from the laminar trend for the largest local Reynolds number tested.…”

Section: Ivd Transition Location and Nosetip Bluntness Effectsmentioning

confidence: 99%

Flow characterization and boundary layer transition studies in VKI hypersonic facilities (Invited)

Grossir

Masutti

Chazot

2015

53rd AIAA Aerospace Sciences Meeting

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A summary of the activities performed over the last years at the von Karman Institute for Fluid Dynamics in the frame of hypersonic boundary layer transition studies is presented. Free-stream noise levels have been determined in the H3 Mach 6 conventional wind tunnel using double hot-wires and modal analysis. In the Longshot wind tunnel at Mach 10, an improved free-stream characterization method, based on the use of free-stream static pressure probes, has been applied, alleviating the needs for the limiting adiabatic and isentropic nozzle flow assumptions. Based on these improved flow characterization, natural transition experiments have been performed in both wind tunnels on 7 • half-angle conical geometries at 0 • angle of attack and with different nosetip radii. Measurements techniques include either infrared thermography or flush-mounted fast response thermocouples in order to determine the transition onset location. Boundary layer instabilities are visualized using a LIF-based Schlieren technique at Mach 10, revealing rope-shape structures typical of the second mode disturbances. Wall measurements using fast-response pressure sensors complete the investigations. Dominant boundary layer disturbances at various locations along the cone are determined and compared with theoretical predictions. The corresponding N-factor is inferred for each wind tunnel. A comparison of the different measurement techniques is finally reported. Nomenclature Symbols c Specific heat, J/(kg.K)

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“…A recent review on this subject is given by Schneider. 9 Results of ballistic range transition experiments using smooth-wall conical models launched at supersonic and hypersonic speeds were reported by Sheetz, [10][11][12] Potter, 13,14 and Reda. 15 Effects of distributed roughness on blunt body transition at hypersonic speeds were investigated in the ballistic range experiments of Reda.…”

mentioning

confidence: 82%

Transition Experiments on Large Bluntness Cones with Distributed Roughness in Hypersonic Flight

Reda

Wilder

Prabhu

2012

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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Large bluntness cones with smooth nosetips and roughened frusta were flown in the NASA Ames hypersonic ballistic range at a Mach number of 10 through quiescent air environments. Global surface intensity (temperature) distributions were optically measured and analyzed to determine transition onset and progression over the roughened surface. Real-gas Navier-Stokes calculations of model flowfields, including laminar boundary layer development in these flowfields, were conducted to predict values of key dimensionless parameters used to correlate transition on such configurations in hypersonic flow. For these large bluntness cases, predicted axial distributions of the roughness Reynolds number showed (for each specified freestream pressure) that this parameter was a maximum at the physical beginning of the roughened zone and decreased with increasing run length along the roughened surface. Roughness-induced transition occurred downstream of this maximum roughness Reynolds number location, and progressed upstream towards the beginning of the roughened zone as freestream pressure was systematically increased. Roughness elements encountered at the upstream edge of the roughened frusta thus acted like a finite-extent "trip array", consistent with published results concerning the tripping effectiveness of roughness "bands" placed on otherwise smooth surfaces. Nomenclature

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Boundary layer transition on supersonic cones in an aeroballistic range

Cited by 8 publications

References 7 publications

Receptivity of Hypersonic Boundary Layers to Acoustic and Vortical Disturbances (Invited)

Receptivity of Hypersonic Boundary Layers to Acoustic and Vortical Disturbances (Invited)

Flow characterization and boundary layer transition studies in VKI hypersonic facilities (Invited)

Transition Experiments on Large Bluntness Cones with Distributed Roughness in Hypersonic Flight

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