One atmospheric phenomenon that adversely affects laser propagation is optical turbulence. From ten months of observation, the refractive index structure constant in the atmospheric boundary layer was found to be significantly reduced under widespread cloudy conditions. The refractive index structure constant (C(n) (2)) depends upon the turbulent flux of momentum, sensible and latent heat. The intensity of a propagating laser beam will not be degraded nearly as much as would be expected under clear or lightly scattered cloud conditions. New experimental data are presented that support this hypothesis. The refractive index structure constant was measured for various cloud-cover conditions.
This paper describes hypersonic interceptor aero-optics performance predictions. It includes code results for three-dimensional shapes and comparisons to initial experiments. It covers the aerothermal, aerodynamic computational codes that are capable of covering the entire flight regime from subsonic to hypersonic flow and includes chemical reactions and turbulence. Heat transfer to the various surfaces is calculated as an input to cooling and ablation processes. The aero-optics codes determine the effect of the mean flowfield and turbulence on the tracking and imaging capability of on-board optical sensors. This paper concentrates on the latter aspects.Nomenclature area, m 2 speed of sound, m/s tip correlation function speed of light, m/s aperture (lens) diameter tilt compressibility correction term focus correction, m~! intensity at focal plane, w/cm 2 wave number 2ir/X, m~' path length, m turbulence scale length, m Mach number index of refraction pressure, N/m 2 distance, m temperature, K time, s velocity, m/s scalar electric field, V/m coordinates, m Gladstone-Dale constant, m 3 /g rate of turbulence dissipation, j/kg-s coordinates of ray pierce point of a CFD cell, m orthogonal separation distances at the aperture turbulent kinetic energy, j/kg wavelength, m density, kg/m 3 ; dimensionless distance between rays at the aperture angle from centerline of focal plane optical path length, m modulation transfer function z dummy variable Subscripts 2 = on surface of cone A = aperture c -coolant at exit FF = flow field Presented as Paper 93-2675 at the 2nd AIAA/
SUMMARY
A review of the literature of iris suture studies in rabbits, monkeys, and man reveals that all studies have been limited to six months or less. This project addresses the longevity of 10-0 prolene as an iris suture in vivo in the rabbit over a two-year period. Light and scanning electron microscopy examination demonstrated 10-0 prolene as relatively non-degradable and inert.
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