The Origin of Aerodynamic Instability of Supersonic Inlets at Subcritical Conditions
Memorandum presenting an investigation of the phenomenon of the starting of aerodynamic instability or buzz in supersonic inlets with external compression. The starting of the buzz has been related to the existence in the flow field of a velocity discontinuity across a vortex sheet which originates at a shock intersection. Results regarding the inlets without separation on the central body, inlets with separation on the central body, the regulation of entering volume flow at angles of attack, experimental performance of various inlets, and an application of the results are provided.
Abstract : This thesis presents a study of radiation patterns for low-gain antennas installed on aircraft. With the aid of the computer program APATCH, a simulation of the radian on patterns for a given antenna located at various points on an aircraft structure can he evaluated. The program uses a technique referred. to as Shooting and Bouncing Rays (SBR), which is valid for structures that have typical dimensions of ten wavelengths or more. A Cessna 172 aircraft with a quarter-wavelength monopole antenna and an F-18 aircraft with a telemetry antenna are analyzed.