Potential and viscous flow in VTOL, STOL or CTOL propulsion system inlets

A method has been developed for analyzing the flow in subsonic axisymmetric inlets at arbitrary conditions of freestream velocity, incidence angle, and inlet mass flow. An improved version of the method is discussed and comparisons of results obtained with the original and improved methods are given. Comparisons with experiments are also presented for several inlet configurations and for various conditions of the boundary layer from insignificant to separated. The paper discusses applications of the method, with several examples given for specific cases involving inlets for VTOL lift fans and for STOL engine nacelles.