Modified compressible turbulence phase distortion formula and compressible turbulence spectrum simulation

Abstract

In order to better study the imaging characteristics of high-speed moving targets in atmospheric turbulence, it is necessary to solve the optical distortion caused by aerodynamic optical effects, and the optical distortion needs to be described by compressible turbulence spectrum. In order to better understand the spectral characteristics of aero-optical distortion, according to the Maxwell equation, the Boltzmann factor equation is introduced based on the existing compressible turbulence spectrum theory, and the analytical expression of the modified compressible turbulence spectrum is derived and verified. Then, based on the freezing theory, the compressible turbulence spectrum is simulated by the phase screen method of power spectrum inversion. The influence of the distance from the moving target wall and turbulence intensity on the compressible turbulence phase screen is simulated and analyzed. Compared with atmospheric turbulence, it is found that the intensity of turbulence is proportional to the compressible turbulence, but the compressible turbulence is also inversely proportional to the distance of the moving target wall. As the distance from the moving target wall decreases, the phase fluctuation of the compressible turbulence is larger, which also indicates that the aero-optical effect mainly occurs in the boundary layer annex of the moving target, and the nearer the target, the aero-optical effect becomes more serious.