Hot-Wire Measurements of Instabilty Waves on Cones at Mach 6

Rufer, Shann J.; Schneider, Steven P.

doi:10.2514/6.2006-3054

Cited by 12 publications

(10 citation statements)

References 8 publications

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“…with the increasing nose radius 0.0001, 0.03125, and 0.0625 in., respectively. Rufer and Schneider [6] measured mass flux profiles over 7…”

mentioning

confidence: 99%

“…In supersonic and hypersonic boundary layers, one important geometrical parameter is nose bluntness. The effects of bluntness on transition in supersonic and hypersonic boundary layers have been studied experimentally [1][2][3][4][5][6] and numerically [7][8][9][10][11][12][13] by many researchers. It was identified that the entropy layer that is formed near the bow shock region persists for a long distance downstream and makes the boundary layer more stable when compared to the sharpcone case.…”

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confidence: 99%

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Effects of Nose Bluntness on Hypersonic Boundary-Layer Receptivity and Stability over Cones

2011

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The receptivity to freestream acoustic disturbances and the stability properties of hypersonic boundary layers are numerically investigated for boundary-layer flows over a 5 straight cone at a freestream Mach number of 6.0. To compute the shock and the interaction of the shock with the instability waves, the Navier-Stokes equations in axisymmetric coordinates were solved. In the governing equations, inviscid and viscous flux vectors are discretized using a fifth-order accurate weighted-essentially-non-oscillatory scheme. A third-order accurate total-variationdiminishing Runge-Kutta scheme is employed for time integration. After the mean flow field is computed, disturbances are introduced at the upstream end of the computational domain. The appearance of instability waves near the nose region and the receptivity of the boundary layer with respect to slow mode acoustic waves are investigated. Computations confirm the stabilizing effect of nose bluntness and the role of the entropy layer in the delay of boundary-layer transition. The current solutions, compared with experimental observations and other computational results, exhibit good agreement. Nomenclature = streamwise wave number C recpt = receptivity coefficient c p = specific heat at constant pressure c v = specific heat at constant volume E = total energy e = molecular internal energy F, G = inviscid flux vector in the axial and radial directions

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“…with the increasing nose radius 0.0001, 0.03125, and 0.0625 in., respectively. Rufer and Schneider [6] measured mass flux profiles over 7…”

mentioning

confidence: 99%

mentioning

confidence: 99%

Effects of Nose Bluntness on Hypersonic Boundary-Layer Receptivity and Stability over Cones

2011

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“…Second-mode instability waves have been studied in the past and measurements were made under quiet and noisy conditions in the BAM6QT [30,31]. The ultimate motivation for developing this instrument is to complement measurements made on the surface of cone models by S. J. Rufer using hot wires, and by M. Estorf using flush mounted pressure transducers [30][31][32].…”

Section: Motivation and Backgroundmentioning

confidence: 99%

“…The ultimate motivation for developing this instrument is to complement measurements made on the surface of cone models by S. J. Rufer using hot wires, and by M. Estorf using flush mounted pressure transducers [30][31][32].…”

Section: Motivation and Backgroundmentioning

confidence: 99%

Oscillations in a Forward-Facing Cavity Measured Using Laser-Differential Interferometry in a Hypersonic Quiet Tunnel

Segura¹

2007

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AFOSR/NAUnclassified and Approved for Public Release M.S. thesis by Rodrigo Segura with development of LDI for Mach-6 quiet tunnel and measurements in Mach-4 quiet tunnel Laminar-turbulent transition is a pivotal factor for the design of hypersonic vehicles but the mechanisms that induce transition are not well understood. A laser differential interferometer (LDI) is a non-intrusive optical device that measures the optical path length difference between two laser beams. The LDI is a reliable calibrated instrument to assist the study of boundary layer instability-wave growth in hypersonic flow and has high sensitivity and frequency response. An LDI with a commercial balanced photodetector capable of detecting optical path length differences of lambda/21,000 from DC to 80 MHz was assembled and tested in the Purdue Quiet-Flow Ludwieg tube. Fluctuations in the subsonic region of a forward-facing cavity were measured with the LDI and compared to those detected with a Kulite pressure transducer at the base of the cavity. Predictions of self-resonating deep cavities were confirmed. The LDI was then adapted and transferred to the Boeing/AFOSR Mach-6 Quiet Tunnel. to give special thanks to Joan Jackson; she made me laugh and was patient and helpful even when I demanded her help on rather short notice. Joe Kline's technical assistance is appreciated.A great deal of contribution came from my fellow researchers.

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“…The understanding of this phenomenon is of great importance because receptivity connects the amplitude of the free-stream disturbances and initial amplitude of the unstable waves 9 . Recent experimental [9][10][11][12][13] , theoretical [14][15][16][17][18][19] and computational [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] studies increased our understanding about receptivity mechanism. However it still remains as a challenging problem with practical importance.…”

Section: Introductionmentioning

confidence: 99%

Effects of Wall Cooling on Hypersonic Boundary Layer Receptivity over a Cone

Kara

Balakumar

Kandil

2008

38th Fluid Dynamics Conference and Exhibit

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E ffects of wall cooling on the receptivity process induced by the interaction of slow acoustic disturbances in the free-stream are numerically investigated for a boundary layer flow over a 5-degrees straight cone. T he free-stream M ach number is 6.0 and the Reynolds number is 7.8x10 6 /ft. Both the steady and unsteady solutions are obtained by solving the full Navier-Stokes equations using 5 th -order accurate weighted essentially non-oscillatory (W E N O) scheme for space discretization and using 3 rd -order total variation diminishing (T V D) Runge-K utta scheme for time integration. Computations are performed for a cone with nose radius of 0.001 inch for adiabatic wall temperature (T aw ), 0.75*T aw , 0.5*T aw , 0.40*T aw , 0.30*T aw , and 0.20*T aw . O nce the mean flow field is computed, disturbances are introduced at the upstream end of the computational domain. Generation of instability waves from leading edge region and receptivity of boundary layer to slow acoustic waves are investigated. Computations showed that wall cooling has strong stabilization effect on the first mode disturbances as was observed in the experiments. T ransition location moved to upstream when wall cooling was applied It is also found that the boundary layer is much more receptive to fast acoustic wave (by almost a factor of 50). W hen simulations performed using the same forcing frequency growth of the second mode disturbances are delayed with wall cooling and they attained values two times higher than that of adiabatic case. In 0.20*T aw case the transition Reynolds number is doubled compared to adiabatic conditions. T he receptivity coefficient for adiabatic wall case (804 °R) is 1.5225 and for highly cooled cones (241, and 161 °R); they are in the order of 10 -3 .

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Hot-Wire Measurements of Instabilty Waves on Cones at Mach 6

Cited by 12 publications

References 8 publications

Effects of Nose Bluntness on Hypersonic Boundary-Layer Receptivity and Stability over Cones

Effects of Nose Bluntness on Hypersonic Boundary-Layer Receptivity and Stability over Cones

Oscillations in a Forward-Facing Cavity Measured Using Laser-Differential Interferometry in a Hypersonic Quiet Tunnel

Effects of Wall Cooling on Hypersonic Boundary Layer Receptivity over a Cone

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