Modeling periodic evolution of aero-optical effects caused by supersonic mixing layer

A model used to quantitatively describe the periodic evolution of aero-optical effects caused by supersonic mixing layer was developed. The large eddy simulation (LES) is used to visualize the instantaneous dynamical characteristics of vortices inside the flow field. Firstly, the stability of the mean value of the supersonic mixing layer flow field is determined by the mean value of the image deviation and the optical path difference (OPD). If the vortex structure of the supersonic mixing layer is assumed to be circular after the time-average flow field is stabilized, the image deviation and bore sight error (BSE) will be caused by the beam passing through the structure. By the combination of formula calculation and open model function, the periodic evolution model of main parameters of aero-optical induced by supersonic mixing layer is established. Secondly, the model is verified by different convective Mach numbers (Mc). The results show that the model results are in good agreement with the numerical simulation results at low Mc. As the Mc increases, the vortex structure is stretched, leading to a discrepancy with the model hypothesis. Finally, the applicability and future application prospect of the model are discussed.