Accession Number:

ADA411610

Title:

Structure and Modeling of Optical Wavefronts in High-Reynolds-Number Turbulent Aero-Optic Flows

Descriptive Note:

Final rept. Mar 2002-Jan 2003

Corporate Author:

CALIFORNIA UNIV IRVINE AERONAUTICS ANDFLUID DYNAMICS LABORATORIES

Personal Author(s):

Report Date:

2003-01-27

Pagination or Media Count:

44.0

Abstract:

Two new methods have been developed and demonstrated which are particularly useful for modeling the large-scale and small-scale structure of aerooptical distortions, as well as the refractive fluid interfaces or density interfaces responsible for these distortions, at high compressibility and large Reynolds numbers. The first method, termed the interfacial-thickness approach, enables the examination of optical-wavefront propagation in terms of the physical thickness of the refractive interfaces. Demonstration of this method on experimental data in high-compressibility large-Reynolds-number shear layers has revealed that the high-gradient regions are spatially isolated. This observation has been utilized to propose and demonstrate a new modeling approach where the high-gradient interfaces are the dominant elements necessary to reproduce the large-scale optical distortions at high compressibility. The second method enables the characterization of the physical anisotropic structure of aerooptical wavefronts as a function of scale. This is useful to extrapolate the small-scale structure of aerooptical distortions at high compressibility to larger Reynolds numbers. These two new techniques enable the modeling of large-scale and small-scale aerooptical behavior at high-compressibility flow conditions relevant to high-speed flight. and are important for Air Force applications involving laser beam propagation in high-speed flight such as for tactical fighter aircraft.

Subject Categories:

  • Aerodynamics
  • Fluid Mechanics
  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE