21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-3.10.4

PLIF IMAGING OF THE SEPARATED REGION BEHIND A CONE IN A HYPERSONIC FLOW

O'Byrne S., Palma P. C., Danehy P. M., Mudford N. R.*, Gai S. L.*, Houwing A. F. P.
Australian National University, Australia; Australian Defence Force Academy, Australia

Keywords: plif imaging, separated region, cone, hypersonic flow

Experiments have been performed which examine the development of separated flow in the near-wake of a cone in a hypersonic free stream. Planar laser-induced fluorescence (PLlF) has been successfully used to visualise the flow around the base of the cone in a Mach 7.6 free stream at various times after the onset of flow. The images show the time-evolution of the main features of the separated flow. They also demonstrate that the shock tunnel flow time is sufficiently long-lived to establish a steady flow in the shock layer. There is, however, evidence to suggest that the flow in the separated region did not reach a steady state during the 400 microseconds after shock reflection. Calculations based upon previous pressure data for base flows behind spheres appear to underestimate the establishment time for the separated flow behind the cone.

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