Near- and farfield measurements of aero-optical effects due to propagation through hypersonic flows

Aero-Optical Effects of Supersonic Boundary Layers

“…Later, these experimental results were further analyzed by Sutton [11], where he calculated length scales and provided a simple scaling for optical modulation transfer function to compute the level of optical degradation caused by compressible boundary layers for different flight regimes. Yanta et al [12], reported measurements of aero-optical distortions by a flatplate laminar boundary layer in a hypersonic facility at M 7. They reported both near-field wave-front measurements and far-field intensities.…”

Measurement of lens focal length with Hartmann–Shack wavefront sensor based on 4F system

“…While these sensors were used for adaptive optics in astronomy and high-energy lasers, they have been applied to a wide range of problems recently, including laser beam characterization [5,6], fluid turbulence measurement [7][8][9], optical system alignment [10], ophthalmic metrology [11], wafer metrology [12], optical metrology for both large [13] and small [14] optics. The basic measurement principle is similar to the Hartmann test of the early 1900s.…”

Yip - Development and Application of a High-Speed Three-Dimensional Density Measurement Technique for Aero-Optic Applications

“…Furthermore, unsteady flow fields, such as those associated with turbulent boundary layers and separated shear layers, are marked by fluctuating timescales (several kHz) beyond the limit of current adaptive optic systems. Nonetheless, past investigations have succeeded in using a variety of experimental methods to characterize the spatial and temporal scales of turbulent flow fields and the resulting wavefront aberrations [ (Truman and Lee 1990) (Chew and Christiansen 1993) (Hugo, et al 1997) (Dimotakis, Catrakis and Fourguette 2001) (Yanta, et al 2000) (Jumper and Fitzgerald 2001) (Stanek, et al 2002) (Wyckham 2003) (Aguirre, et al 2005)]. A common limitation of these efforts, however, is the lack of density field data.…”