A novel experimental test setup has been assembled to simulate the primary aero-optical effects encountered by a cooled window on a hypersonic interceptor. Although the equipment was located in an ambient laboratory environment, emulation of the principal flight level aero-optical effects should be possible with some modification to the equipment. The test hardware and preliminary results from a proof -of-principle demonstration are presented in this paper.
A unique experimental apparatus has been designed and constructed to characterize aero-optical distortions related to the turbulent flow conditions experienced by a windowed hypersonic vehicle. Using this apparatus, a series of imaging tests was conducted with a classical mixing/shear layer traveling at approximately 600 mIs. The experimental setup consisted of a collimated 0.84 mm laser diode point source that was passed through the flow field and imaged onto a CCD array. During a one second stable flow period, 92.5 frames of images were collected. Several runs were made with the lasr diode operating in both continuous and pulsed (40is duration) modes. These images were used to investigate several effects such as, image blur, jitter, and strehl loss. For long integration periods, the image experienced an average image blur circle size increase of approximately 24 times from the "wind-off" case. The pulsed runs showed an increase in jitter of approximately 36.4 j.trad. In addition, during continuous runs, a strehl ratio of approximately 0.0026 was observed. These and other preliminary results correlated well with theoretical predictions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.