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Proceedings Paper

Laser propagation in aircraft wakes
Author(s): Alan R. Shapiro
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Paper Abstract

The use of lasers aboard aircraft is affected by the perturbed airflow in its vicinity. Therefore, an ability to predict the structure of aircraft-induced turbulence would be useful in system and performance analysis. PSR performed temperature and velocity fluctuation measurements in the wakes of an NRA-3B and a B-1B at trail distances of 50 to 5500 m, at two Mach numbers (0.5 and 0.75) and at two altitudes (0.9 and 6 km). Preliminary analysis of the data suggested significant differences with the predictions of the computational fluid dynamics code (CFD) WAKE developed for this application by ARAP for U.S. Air Force. These differences impact laser propagation. The principal difference between the data and the CFD predictions is that the temperature fluctuations which determine C2N are not isotropic and exhibit spectra and correlation scales which differ greatly from those of velocity. This paper reports the development of a hypothesis concerning the source of this temperature structure in aircraft wakes. Modifications to CFD models are suggested.

Paper Details

Date Published: 2 December 1993
PDF: 16 pages
Proc. SPIE 2005, Optical Diagnostics in Fluid and Thermal Flow, (2 December 1993); doi: 10.1117/12.163698
Show Author Affiliations
Alan R. Shapiro, Pacific-Sierra Research Corp. (United States)


Published in SPIE Proceedings Vol. 2005:
Optical Diagnostics in Fluid and Thermal Flow
Soyoung Stephen Cha; James D. Trolinger, Editor(s)

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