Measurement of Hypersonic Boundary Layer Transition on Cone Models in the Free-Piston Shock Tunnel HIEST

Tanno, Hideyuki; Komuro, Tomoyuki; Sato, K.; Itoh, Katsuhiro; Takahashi, M.; Fujii, Keisuke

doi:10.2514/6.2009-781

Cited by 32 publications

(22 citation statements)

References 4 publications

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“…These amplification values are high as compared to the more typical value of N ≈ 5-6 usually characterizing a 'noisy' tunnel (Schneider 2001), but consistent with the expected difference in receptivity for the high-frequency second-mode instability as compared to the relatively low-frequency noise in the T5 free stream as measured by Parziale et al (2014). This is supported by the recent analysis of Gronvall, Johnson & Candler (2014), who found a transition onset value of N ∼ 8 for the shock-tunnel experiments of Tanno et al (2009).…”

Section: Focused Laser Differential Interferometrysupporting

confidence: 85%

“…This is in contrast to the harsh mechanical environment of reflected-shock tunnels like T5. However, given the success of past efforts (Adam & Hornung 1997;Germain & Hornung 1997;Rasheed et al 2002) in T5, as well as other researchers using shock tunnels (Tanno et al 2009;Laurence et al 2012Laurence et al , 2014a to study stability and transition, we felt confident that measurement solutions could be found.…”

Section: Measurement Of Second-mode Instabilitymentioning

confidence: 99%

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Observations of hypervelocity boundary-layer instability

2015

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A novel optical method is used to measure the high-frequency (up to 3 MHz) density fluctuations that precede transition to turbulence within a laminar boundary layer in a hypervelocity flow. This optical method, focused laser differential interferometry, enables measurements of short-wavelength, high-frequency disturbances that are impossible with conventional instrumentation such as pressure transducers or hot wires. In this work, the T5 reflected-shock tunnel is used to generate flows in air, nitrogen and carbon dioxide with speeds between 3.5 and 5 km s ), density fluctuations are observed to grow in amplitude and transition from a single narrow band of frequencies consistent with the Mack or second mode of boundary-layer instability to bursts of large-amplitude and spectrally broad disturbances that appear to be precursors of turbulent spots. Disturbances that are sufficiently small in initial amplitude have a wavepacket-like signature and are observed to grow in amplitude between the upstream and downstream measurement locations. A cross-correlation analysis indicates propagation of wavepackets at speeds close to the edge velocity. The free stream flow created by the shock tunnel and the resulting boundary layer on the cone are computed, accounting for chemical and vibrational non-equilibrium processes. Using this base flow, local linear and parabolized stability (PSE) analyses are carried out and compared with the experimental results. Reasonable agreement is found between measured and predicted most unstable frequencies, with the greatest differences being approximately 15 %. The scaling of the observed frequency with the inverse of boundary-layer thickness and directly with the flow velocity are consistent with the characteristics of Mack's second mode, as well as results of previous researchers on hypersonic boundary layers.

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Section: Focused Laser Differential Interferometrysupporting

confidence: 85%

Section: Measurement Of Second-mode Instabilitymentioning

confidence: 99%

Observations of hypervelocity boundary-layer instability

2015

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“…Parziale et al [25] found that noise in the T5 freestream was relatively low frequency compared with the most unstable boundary-layer frequencies. This hypothesis was implicitly supported by the recent analysis of Gronvall et al [28], who found a transition onset value of N ≈ 8 for the experiments of Tanno et al [12], which were also performed in a reflected-shock tunnel, although at lower enthalpy than the present study, and for a limited range of conditions, with unspecified cleaning procedures. At the start of the present test campaign, before the implementation of the cleaning regimen, we encountered difficulty in achieving repeatable transition Reynolds numbers and N factors.…”

Section: Introductionsupporting

confidence: 74%

“…One such ground-test facility to generate "high-enthalpy" flows is the reflected-shock tunnel. In the past, researchers have used shock tunnels and reflected-shock tunnels to study BLT [7][8][9][10][11][12][13]. More recently, in the high-enthalpy reflected-shock tunnel at Gottingen, Germany (HEG), Laurence et al [14][15][16] reported a schlieren-based technique for the investigation of disturbances in hypervelocity boundary layers.…”

Section: Introductionmentioning

confidence: 99%

Effects of Shock-Tube Cleanliness on Hypersonic Boundary Layer Transition at High Enthalpy

et al. 2017

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“…Other measurements have since been made with these sensors in multiple tunnels under noisy and quiet flow. [7][8][9] These sensors show promise for being able to measure boundary-layer instabilities in many hypersonic wind tunnels.…”

Section: Introductionmentioning

confidence: 99%