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A flow modeling method has been developed to analyze the flow in the annular base (rear-facing surface) of a circular engine nacelle flying at subsonic speed but with a supersonic exhaust jet. Real values of exhaust gas properties and temperature are included. Potential flows of the air and gas streams are computed for the flow past a separated wake. Then a viscous jet mixing is superimposed on this inviscid solution. Conservation of mass, momentum and energy is achieved by mutiple iterations. Despite the iterations, the wake flow field is computed with modest computer requirements.

Electro-Impulse De-Icing (EIDI) has been studied and developed at Wichita State University for the past six years in ten icing wind tunnel tests and three sets of flights tests. However, questions remained about the system endurance over a lifetime of use and about electromagnetic compatibility. These were addressed in tests of both metal and composite leading edges. Energy levels used were those determined necessary in the earlier tunnel and flight tests. Failures for the aluminum leading edges were found only in poorly designed coil brackets and in a pre-stressed rivet hole. No damage could be found with the composite model. Electromagnetic radiation was found to be well contained in an aluminum wing. Exposed lead wires were high power emitters and these had to be fully shielded for the composite model to meet the specifications. The emissions were broadband with no significant peak frequencies. ICE ACCUMULATION IN FLIGHT is a well recognized danger.