Boundary-layer disturbances are analysed on a $5^{\circ }$ half-angle blunted cone in Mach 5, high-enthalpy flow ( $h_0 = 9\ {\rm MJ}\ kg}^{-1}$ ) with low wall-to-edge temperature ratio, $T_w/T_e 0.18$ . Schlieren and focused laser differential interferometry (FLDI) utilized to assess the structures frequency content associated disturbances. Wave packets identified from bursts of modal time-resolved spectrograms. Bandpass filtering, proper orthogonal decomposition (POD) space–time POD then...

The principal goal of the Hypersonic International Flight Research Experimentation (HIFiRE) flight 5 is to measure hypersonic boundary-layer transition on a three-dimensional body. This paper presents measurements heat flux and in Boeing/U.S. Air Force Office Scientific Mach-6 Quiet Tunnel. facility has been developed provide quiet flow at high Reynolds number, with low noise levels comparable flight. Previously, global location front were measured temperature-sensitive paint (TSP). A new...

In this paper, results from two experiments performed at California Institute of Technology’s T5 free-piston reflected shock tunnel are compared to numerical stability computations conducted using various analysis tools. The goal comparison is begin understanding the range boundary-layer transition predictability different approaches for high-enthalpy flows. focused on physics second-mode instability high enthalpy and role high-temperature effects. Although solvers considering thermochemical...

View Video Presentation: https://doi.org/10.2514/6.2022-0734.vid In this paper, a Q-FLDI system was constructed to correlate disturbances inside and outside of the boundary layer over blunted cone in high-enthalpy, hypersonic flow at T5, free- piston-driven reflected-shock tunnel California Institute Technology. We present results for three shots representing fully-turbulent case with 5 mm nose-tip radius, an unstable radius moderate enthalpy (6 MJ/kg), 2 higher (10.5 MJ/kg). case, spectra...

Results from a stability investigation using quad-focused laser differential interferometry (q-FLDI) and high-speed schlieren cinematography of hypersonic flow over cooled uncooled 5◦ half-angle cone are presented in this paper. The frequency phase-speed the largest-amplitude disturbance (largest N factor) as predicted by STABL measured FLDI or were excellent agreement for room-temperature cases good cooled-wall cases. A comparison between room- temperature shot at nominally same Reynolds...

View Video Presentation: https://doi.org/10.2514/6.2023-0289.vid This paper presents an experimental investigation into the boundary-layer stability of a slender cone in hypervelocity flow within T5 reflected-shock tunnel. Schlieren imaging was utilized to characterize frequency content and disturbance structures experienced boundary layer 5◦ Mach-5 freestream with high reservoir enthalpy, 8-10 MJ/kg. The effects varying Reynolds number nose bluntness were examined. Second-mode peaks between...

View Video Presentation: https://doi.org/10.2514/6.2023-0288.vid FLDI is used to characterize an unstable boundary layer on a 5-degree cone. Results from two experiments are presented: shot 2990 represented high-enthalpy condition with 2 mm nosetip and 2955 moderate-enthalpy 5 nosetip. For 2990, the measured frequency of second-mode instability using agreed well results obtained schlieren for experiment performed at similar conditions, was in good agreement maximum N factor stability...

The principal goal of the Hypersonic International Flight Research Experimentation (HIFiRE) flight Five is to measure hypersonic boundary-layer transition on a three-dimensional body. HIFiRE tests are supported by ground test campaign; this paper presents measurements heat flux and in Boeing/AFOSR Mach-6 Quiet Tunnel (BAM6QT). This facility has been developed provide quiet flow at high Reynolds number, with low noise levels comparable flight. Previously, global location front were measured...

In this paper, a numerical and experimental comparison is presented of slightly blunted, 5° half-angle cone at high-enthalpy flow conditions. Experimental studies were conducted California Institute Technology's T5 free piston reflected shock tunnel. Numerical stability investigations with STABL, MAMOUT ONERA, JoKHeR the University Delaware, CHAMPS Maryland. The focuses on second-mode instability physics high-enthalpy. NLDE based solver was most accurate identifying amplified frequency,...

This paper presents an experimental study of the effect wall cooling on boundary-layer structures a sharp-nosed, 5° half-angle cone in Mach 6 flow. An methodology was developed that allowed quantitative measurements second-mode disturbance growth over range wall-temperature ratios from [Formula: see text] without modifying freestream environment. The system comprised probe cooling, liquid nitrogen injection, and thermal insulation. model temperature monitored before each run, with...

View Video Presentation: https://doi.org/10.2514/6.2021-2866.vid The effect of wall cooling is investigated on the boundary layer a 5◦ -half-angle cone in Mach-6 flow. combination active and passive thermal management decreases model temperature Tw by up to 85◦ C. Schlieren imagery used compare cooled uncooled cases, with wall-to-edge ratios 1.67 ≤ /Te 2.35 at Re∞ = 5.3 × 10^6 m−1 . structure, spectral content, growth second-mode wavepackets identified these levels are compared one another....

View Video Presentation: https://doi.org/10.2514/6.2022-1709.vid This paper presents an extended study of the effect cooling on boundary-layer structures and thermal topology a slender cone in Mach-6 flow. A range wall-to-edge temperature ratios 1.64-2.34 was established with active passive management. These conditions were tested at freestream unit Reynolds number Re = 5.2 x 10^6 /m angles attack 0d 4d. In all cases, schlieren imagery utilized to evaluate instabilities within boundary...

This study presents the experimental techniques and analysis utilized to characterize boundary-layer instability mechanisms on a slender cone under cooled-wall conditions. Simulations indicated that, with cooler probe inserted, model would reach thermal equilibrium at -56C. A final configuration, utilizing passive anti-icing management, achieved temperatures as low -58C in region of interest. As high-degree cooling precluded use conventional surface-mounted high-frequency instrumentation,...

A campaign of hypervelocity experiments was conducted with a blunted 5d-half-angle cone in the T5 shock tunnel. modified Z-type schlieren setup utilized to image boundary-layer total enthalpies around 10 MJ/kg and freestream-to-wall temperature ratios approximately 5. Second-mode instabilities transitional behavior boundary layer were identified imaged within field view between x/L = 0.57 0.73. wavepackets manifested as alternating dark/light waves beginning right at wall permeating up 30%...