Parametric Design Study on Aerodynamic Characteristics of Variable Pitot Inlets for Transonic and Supersonic Civil Aviation

This paper reveals the influence of selected geometric parameters on the aerodynamic performance of circular variable aero engine inlets in transonic and supersonic civil aviation. The trade-off in inlet design and aerodynamic evaluation parameters are presented. The approach to investigate the dependencies between the aerodynamic and geometric parameters at different flight conditions by means of a parametric design study is introduced. The dependencies of inlet drag and efficiency from geometric parameters at flight speeds of Mach 0.95 up to Mach 1.6 are identified. Although entailing additional weight, the inlet length represents the parameter with the highest potential for drag reduction by up to 50% in the selected design space. Ideal geometries for variable pitot inlets are determined. After considering weight, their potential range benefit nearly disappears for subsonic applications, but remains above 20% for supersonic flight at Mach 1.6.