@inproceedings{a49e93f552eb4070aca0e8b65bc9efb8,
title = "Instability and transition measurements in the Mach-6 quiet tunnel",
abstract = "The Boeing/AFOSRMach-6 Quiet Tunnel achieved quiet flow to a stagnation pressure of 163 psia in Dec. 2008, the highest value observed so far. It remains quiet at pressures above 160 psia. Under noisy conditions, nozzle-wall boundary-layer separation and the associated tunnel shutdown appear to propagate slowly upstream, whereas under quiet conditions, the propagation is very rapid. A new diffuser insert has been designed, fabricated, and installed in the tunnel in order to start larger blunt models and increase run time. A flared cone with a circular-arc geometry was designed to generate large second-mode N factors under quiet flow conditions. When the computed N factor was 13, large instability waves were measured under quiet flow conditions using fast pressure sensors, but the flow remained laminar. Transition was observed only under noisy conditions. A laminar instability was detected in the wake of an isolated roughness element in the boundary layer on the nozzle wall; this appears to be the first such measurement at hypersonic speeds.",
author = "Wheaton, {Brad M.} and Juliano, {Thomas J.} and Berridge, {Dennis C.} and Amanda Chou and Gilbert, {Peter L.} and Casper, {Katya M.} and Steen, {Laura E.} and Schneider, {Steven P.} and Johnson, {Heath B.}",
year = "2009",
doi = "10.2514/6.2009-3559",
language = "English (US)",
isbn = "9781563479755",
series = "39th AIAA Fluid Dynamics Conference",
publisher = "American Institute of Aeronautics and Astronautics Inc.",
booktitle = "39th AIAA Fluid Dynamics Conference",
}