Joint influences of aerodynamic flow field and aerodynamic heating of the dome on imaging quality degradation of airborne optical systems.

We investigated the joint influences exerted by the nonuniform aerodynamic flow field surrounding the optical dome and the aerodynamic heating of the dome on imaging quality degradation of an airborne optical system. The Spalart-Allmaras model provided by FLUENT was used for flow computations. The fourth-order Runge-Kutta algorithm based ray tracing program was used to simulate optical transmission through the aerodynamic flow field and the dome. Four kinds of imaging quality evaluation parameters were presented: wave aberration of the exit pupil, point spread function, encircled energy, and modulation transfer function. The results show that the aero-optical disturbance of the aerodynamic flow field and the aerodynamic heating of the dome significantly affect the imaging quality of an airborne optical system.

[1]  Dinesh K. Prabhu,et al.  Transition Experiments on Blunt Bodies with Isolated Roughness Elements in Hypersonic Flight , 2010 .

[2]  Moshe Israeli,et al.  Numerical calculation of transitional boundary layers , 1982 .

[3]  Daniel C. Harris,et al.  Materials for Infrared Windows and Domes , 1999 .

[4]  Roberto Vaglio-Laurin,et al.  Turbulent Heat Transfer on Blunt-Nosed Bodies in Two-Dimensional and General Three-Dimensional Hypersonic Flow , 1960 .

[5]  Z. Fan,et al.  Imaging quality evaluation of aerodynamically heated optical dome using ray tracing. , 2010, Applied optics.

[6]  Zongfu Jiang,et al.  Optical path difference of the supersonic mixing layer. , 2010, Applied optics.

[7]  Dinesh K. Prabhu,et al.  Transition Experiments on Blunt Bodies with Isolated Roughness Elements in Hypersonic Free Flight , 2010 .

[8]  L. Lees.  Laminar Heat Transfer Over Blunt-Nosed Bodies at Hypersonic Flight Speeds , 1956 .

[9]  Lars Sjöqvist,et al.  Laser beam propagation through a full scale aircraft turboprop engine exhaust , 2010, Security + Defence.

[10]  Yuanli Cai,et al.  Influence of altitude on aero-optic imaging deviation. , 2011, Applied optics.

[11]  Eugene Frumker,et al.  Generic method for aero-optic evaluations. , 2004, Applied optics.

[12]  Matthew R. Whiteley,et al.  Influence of aero-optical disturbances on acquisition, tracking, and pointing performance characteristics in laser systems , 2011, Defense + Commercial Sensing.

[13]  Markus Henriksson,et al.  Laser beam propagation in close vicinity to a down-scaled jet engine exhaust , 2004, SPIE Security + Defence.

[14]  Tao Wang,et al.  Numerical study of evaluating the optical quality of supersonic flow fields. , 2007, Applied optics.

[15]  Erik Sucher,et al.  Laser beam propagation experiments along and across a jet engine plume , 2008, Security + Defence.