Computational study of the aero-optical imaging degradation of hypersonic vehicles under time-varying velocities

Under conditions of time-varying velocities, turbulent fields exhibiting non-uniform gradients external to the hypersonic vehicle interact with the optical dome, resulting in phenomena such as offset, jitter, blurring, and energy attenuation of target signals. This paper establishes a fluid-structure interaction model for a blunt bi-conic side-window vehicle, utilizing an air-to-air missile as the research context. Based on CFD numerical simulation under time-varying velocities, the aero-optical transmission effect evaluation index is quantitatively calculated utilizing a reverse ray tracing algorithm. This study evaluates the imaging performance of the optical system in terms of light deflection, wavefront transmission distortion, and imaging deviation. The results indicate that the flow field gradually stabilizes after an exposure time of 6 s, while the optical dome gradually stabilizes after 11 s. During the initial phase, the aero-optical transmission effect induced by the aero-optical flow field is the primary contributor to the degradation of imaging performance. As the exposure time increases, the aero-thermal effects within the structural domain intensify, leading to the aero-optical transmission effect caused by the optical window becoming the predominant factor.