| When high speed imaging guided missles are flying in the atmosphere,the compelx flow field around the optical head cover could cause the target image’s displacement,jitter and blurring,which could be called aero-optics,and the precision of target recognizing would be affected finally.The study of the supersonic film aero-optics and distortion correction were focused,related research based on the BOS(Background Oriented Schlieren)technique.The main research contents included the supersonic film mechanism,supersonic film aero-optics and distortion correction based on BOS technique.Through the innovation of experimental model and method,it was realized that the jet Reynolds number could be adjusted widely and measurement of supersonic film wavefront based on near field improved BOS technique.In view of the flow of supersonic film with still mainstream,the typical two layer structure model was used,and the thin shear layer theory was applied to supersonic film.Based on the thin shear layer characteristics at high Reynolds number,the scaling law of supersonic film aero-optics was deduced,the results were in good agreement with the theoretical results.The flow visualization of supersonic film was studied,and the flow characteristics of the two types supersonic film with supersonic and still mainstream were compared.The wavelet analysis was used to study the flow distribution characteristics of the supersonic film.Based on the displacement field results acquired by BOS technique,and two ways to construct the image mapping function,respectively,polynomial fitting method and local weighted average surface function fitting method,the spatial mapping functions between the distorted images and undistorted images were constructed,the distortion caused by the double bonding len and the supersonic film aero-optics were corrected. |
