Investigation on aero-optical effects of high-speed turbulence over a slope with a cavity

It has been numerically studied in this paper that the effects of the cavity's depth on aero-optical property of high-speed turbulence over a slope with a cavity. Turbulence is numerically simulated by a RANS/LES hybrid method i.e. the DES method, coupled with J-B model, and unsteady equations are solved with dual-time step LU-SGS iterative algorithm. In order to analyze wavefront differences on nearfield and blur spot aberrations on farfield, methods such as physical optics, wavefront reconstruction technology etc, are used. The simulated results show that the shallow cavity would induce a shock wave in the front of the cavity, bringing about wavefront tilt stronger, and the deep cavity would produce the separated shear layers and the vortex structures etc, making unsteady property of aero-optical effects more visible. The results also show that aero-optical effects aroused by high-speed turbulence are very severe at the simulated conditions, and wavefront tilt, OPDrms, PV and Strehl ratio reach 69μ rad, 0.22λ, 1.2λ and 0.31 respectively, and their fluctuation values are 38μ rad, 0.04λ, 0.8λ and 0.43.