Profiles of streamwise velocity and fluctuations in a hypersonic turbulent boundary layer using acetone tagging velocimetry

Acetone tagging velocimetry (ATV) with nominally 1% mole fraction acetone seeding was conducted in a shock-tunnel-generated hypersonic turbulent boundary layer over a hollow-cylinder-flare at M-e = 6.05, T-w/T-r = 0.65, Re-theta = 8925, and Re-tau = 408. This single-laser tagging velocimetry experiment measured streamwise velocity and fluctuations, (u) over bar and u(RMS)', had a repetition rate of 50 kHz, and did not require the use of an image intensifier. The ATV data are non-dimensionalized via the van Driest transformation and compares well with the literature down to y(+) approximate to 3; this is into the viscous sublayer. The Morkovin-scaled fluctuations matched the literature for y(+) > 10; however, below y(+) approximate to 10, it appears that the noise introduced by the measurement technique, in addition to the velocity differences being small near the wall, rendered the ATV-measured Morkovin-scaled fluctuations below y(+) = 10 not useful.