Project Title:

Stimulated Brillouin Diagnostics of Hypersonic Flows

02.06-1520
Stimulated Brillouin Diagnostics of Hypersonic
	Flows
Deacon Research
900 Welch Road, Suite 203
Palo Alto, CA 94304
Anthony O'Keefe  (415-326-1520)
JSC -- NAS9-17937

Abstract:

		 Conventional laser Doppler velocimetry fails for supersonic or turbulent flows.
As an alternative, a remote velocity sensor based on stimulated Brillouin scattering
(SBS) was investigated. This innovation should operate reliably both at low and high
speeds and offer the same scanning capability with better time resolution than the
existing technique. Because of the phase conjugation property of SBS resulting in
near 100 percent backscatter, this system provides a unique opportunity for measuring
supersonic airflows in the vicinity of aircraft in flight. Such a capability will
allow a better understanding of the factors limiting the performance envelope of
new and existing airframes and provide benchmark information for the simulation codes
in a parameter range which cannot be reproduced in wind tunnels.
 	Phase I work involved scaling of SBS characteristics based upon both the theoretical
and the experimental investigations of the SBS process reported in the literature.
This study has shown that such a system can be built with commercially available
components.

Potential Commercial Application:

Potential Commercial Application: This new technology is expected to play an important
role in the development of new high speed airframes and conceivably in the extension
of the performance envelope of existing ones.