Numerical analysis and prediction of Aero-optical effects

Abstract

Shell models of turbulence were used to study the effect of isotropic turbulence on the refractive index spectrum for the case of a plane wave beam propagation through turbulent flow.Existing theories of the 1D and 3D temperature spectra were shown to be inaccurate in the dissipative range of the spectrum due to unresolved scales at high Reynolds numbers. The shell model explaining the buoyancy driven turbulence was chosen as a tool to consider density changes with temperature and resolve all the range of wavenumbers up to the Kolmogorov's scale. The physical nature of the Hill bump (increase of the slope of the energy spectrum), observed in the transition region between inertial-convective and viscous-diffusive parts of the cascade was

Research on the influence of aero-optical effects on starlight atmospheric refraction navigation under supersonic conditions

“…The unique technical advantages of starlight atmospheric refractive navigation make it more and more important in the military, the high-precision, low-cost, miniaturized and fully autonomous starlight atmospheric refractive navigation technology has become the future development trend [1][2][3]. When the aircraft is at supersonic speed, the shock waves, turbulent boundary layer, a shear layer will be formed in the surrounding atmosphere, this complex airflow field will lead to the uneven atmosphere density, which will result in offset, blur, jitter and energy attenuation of the target image in the imaging system.…”