Approach for two-dimensional velocity mapping

作者：Abado Shaddy^*; Gordeyev Stanislav; Jumper Eric

来源：Optical Engineering, 2013, 52(7): 071402.

DOI：10.1117/1.OE.52.7.071402

• aero-optics
• adaptive-optics
• Malley probe
• four-beam Malley probe
• proper orthogonal decomposition
• Airborne Aero-Optics Laboratory
• hemisphere-on-cylinder turret
• flat windowed turret

A method for extracting the convection speed and direction of aberrations present in wavefronts due to aero-optical turbulence over the pupil of a turret on the side of an airborne platform is addressed. The method is applied to data from the Airborne Aero-Optics Laboratory (AAOL). Such convection information is useful in designing feed-forward adaptive-optic approaches. The method makes use of a four-beam Malley probe technique derived by constructing a two-dimensional (2-D) local convective velocity-distribution over the beam's aperture. This technique is based on extending the analysis of the Notre-Dame-developed Malley probe. Two wavefront datasets (Azimuth 157 deg and Elevation 40 deg; Azimuth 42 deg and Elevation 43 deg) from the AAOL are analyzed using the derived method, the first where the laser propagates through fully-separated flow and the second where the laser propagates through an attached-flow region. Finally, the 2-D proper orthogonal decomposition is applied to one in-flight measured dataset to determine the spatial requirements of deformable mirrors in an adaptive-optics system. The paper concludes with a discussion that points out the usefulness of the 2-D velocity-distributions in characterizing the various flow structures which convect over the aperture.

• 出版日期2013-7