In this work we investigate optical distortions caused by the existence of a turbulent shear layer in a beam path. We look at several propagation paths and evaluate the loss of resolution caused by the inhomogeneous layer located at various distances from the transmitter.
We use our wave-optics code for atmospheric propagation and implement into it propagation through a shear layer. Thus we are able to calculate a combined beam propagation, either emanating from the optical window or incoming from an outside source. The fluctuations of the index of refraction are calculated using the Wye's model
The impact of aerodynamic flow upon the performance of an airborne optical system is becoming a critical issue in the development and engineering of IR electro-optic systems. The analysis of this impact is now in the state of the art of IR electro-optic system research. Significant effort has been made on this issue during recent years. In this work we describe a novel technique for aero-optic calculations. The technique is based on commercially available software. In this work CodeV is the optical ray tracing code and Fluent is the Computational Fluid Dynamics (CFD) code. The synergetic combination between the output of the CFD code and optical software leads to the development of the method. The optically relevant data from the CFD results is transformed into index of refraction field and introduced as an input to the optical code. It is important to note that the data must not necessarily be presented in an analytical form; rather it is introduced in the most general form - as a discrete set of values located at a non-uniform grid of points.
The modified quadratic Shepard method has been adopted for the data interpolation. This enables a simple interface with virtually any software output. Such compatibility ensures that the technique can be easily extended for the solution of a whole spectrum of optical problems that involve arbitrary index of refraction changes in the bulk and arbitrary optical surface shapes. For example image quality degradation caused by dome heating can be easily assessed. Both index of refraction changes of the dome and dome shape distortion being taken into account. Several numerical simulations demonstrating the technique are presented.