Methods for Reducing Turbulent Flow Aero-Optical Distortion

摘要

Methods for reducing the aero-optical distortion which affects jet-cooled seekerwindows on high-speed, endo-atmospheric interceptors were studied. Reductions in turbulence were achieved by curving the shear layer in the streamwise direction. This type of curvature corresponds to a window whose outer surface is convex in the axial direction. For a case with moderate curvature, the peak shear stress and density fluctuations were reduced by 85% compared to an otherwise similar flat shear layer. The optical properties of the shear layers were evaluated using a simple ray-tracing method, and the aero-optical distortion was significantly reduced by the stabilizing curvature. Another control concept that was tested involved lateral convergence imposed upon the shear layer. This concept was unsuccessful from an aero-optics view point because the turbulent shear stress roughly doubled relative to the unmodifled shear layer.... Turbulence, optical distortion, Turbulence control, Large eddy simulation.