Bibliographic Details
| Title: |
Aero-Optical Wavefronts and Scale-Local Charcterization in Large-Reynolds-Number Compressible Turbulence. |
| Authors: |
Aguirre, Roberto C.1, Catrakis, Haris J.1 catrakis@uci.edu, Atassi, H. |
| Source: |
AIAA Journal. Oct2004, Vol. 42 Issue 10, p1982-1990. 9p. 8 Diagrams. |
| Subjects: |
Aerodynamics, Fluid dynamics, Turbulence, Mechanical engineering, Mechanical movements, Holography, Optics |
| Abstract: |
A new technique is proposed that enables the scale-local characterization of aero-optical wavefronts. Because optical wavefronts degraded by turbulent flows are physically highly anisotropic and exhibit distortions over a wide range of scales, a method is needed to examine the wavefront structure at varying degrees of anisotropy and as a function of scale. We introduce an aero-optical-wavefront-anisotropy (AWA) parameter as the ratio of scaling factors for the wavefront distortions and for the wavefront transverse extent. This AWA parameter, combined with box counting, enables a scale-local anisotropic examination of the wavefronts. We demonstrate this technique on wavefronts derived from experiments on large-Reynolds-number (Re ∼ 106) high-compressibility (Mc ∼ 1) turbulent shear layers between dissimilar-index-of-refraction gases. Variation of the AWA parameter and scale-local examination of the distortions reveal the presence of anisotropic self-similarity, or self-affinity, at small scales spanning nearly a decade. This finding shows the utility of the technique to detect scaling in large-Reynolds-number flow experiments from the aero-optical behavior. The present finding and technique provide key ingredients to extrapolate the small-scale properties of compressible-flow aero-optical wavefronts to higher Reynolds numbers and are also useful for modeling and for computational aero-optics. [ABSTRACT FROM AUTHOR] |
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| Database: |
Engineering Source |
