Nanoparticle-based planar laser scattering was used to measure the density distribution of the supersonic (Ma=3.0) turbulent boundary layer and the optical path difference (OPD), which is quite crucial for aero-optics study. Results were obtained using ray tracing. The influences of different layers in the boundary layer, turbulence scales, and light incident angle on aero-optics were examined, and the underlying flow physics were analyzed. The inner layer plays a dominant role, followed by the outer layer. One hundred OPD of the outer layer at different times satisfy the normal distribution better than that of the inner layer. Aero-optics induced by the outer layer is sensitive to the filter scale. When induced by the inner layer, it is not sensitive to the filter scale. The vortices with scales less than the Kolmogorov scale (=46.0  μm) have little influence on the aero-optics and could be ignored; the validity of the smallest optically active scale (=88.1  μm) proposed by Mani is verified, and vortices with scales less than that are ignored, resulting in a 1.62% decay of aero-optics; the filter with a width of 16-grid spacing (=182.4  μm) decreases OPD by 7.04%. With the increase of the angle between the wall-normal direction and the light-incident direction, the aero-optics becomes more serious, and the difference between the distribution of the OPD and the normal distribution increases. The difficulty of aero-optics correction is increased. Light tilted toward downstream experiences more distortions than when tilted toward upstream at the same angle relative to the wall-normal direction.

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The aero-optical effects induced by the complex flow structure around a hypersonic optical dome is highly unsteady, which leads to significant differences in the imaging quality under different exposure times. It is of great significance to study the influence of exposure time on imaging quality for guiding the design of imaging guidance seekers and improving imaging guidance accuracy. Based on the hypersonic gun wind tunnel, an aero-optical effect measurement platform was built to measure the wavefront from transient exposure to long exposure. With the increase of exposure time, the accuracy of high-order optical path difference (OPD) reconstruction by low-order Zernike polynomials increased from 62.2% to 88.6%. The increase of exposure time was helpful to reduce the complexity of the wavefront spatial distribution structure. In principle, it could reduce the difficulty of wavefront adaptive correction systems. With the increase of exposure time, the O P D r m s corresponding to O P D h i g h − o r d e r increased gradually, the amplitude decreased gradually, and the difference of O P D r m s decreased gradually at different times. Under different exposure times, the large-aperture approximation principle could achieve a better prediction of Strehl ratio values. With the increase of exposure time, the imaging integral resolution, R , decreased obviously, and it was stable at about 1.43 R 0 . Compared with that, R was improved by about 30% when the exposure time was 6 ns.