OPTIMIZATION OF HYPERSONIC WAVERIDERS DERIVED FROM CONE FLOWS - INCLUDING VISCOUS EFFECTS

Over the past two years, interest in all aspects of hypersonic flight has grown explosively, driven by new vehicle concepts such as the aerospace plane, aero-assisted orbital transfer vehicles, and hypersonic cruise vehicles, to name a few.; High lift-to-drag ratio (L/D) is important for one reason or another to almost all of the hypersonic vehicle concepts currently under investigation, yet it is well known that high values of L/D are very difficult to obtain at hypersonic speeds, due to the presence of strong shock waves (hence high wave drag) and massive viscous effects. In fact, there is a general empirical correlation by Kuchemann based upon actual flight data for (L/D)(,max) as a function of Mach number, given by (L/D)(,max) = 4(M(,(INFIN)) + 3)/M(,(INFIN)) which represents a type of "L/D barrier" that most real flight vehicles are unable to break.; It has been the purpose of the present work to develop a new class of hypersonic vehicles that exceed this "L/D barrier". The vehicles are waveriders with windward surfaces derived from conical flows and optimized for maximum L/D. Included in the waverider analysis are upper surfaces derived from axisymmetric expansion flows, blunted leading edges to satisfy aerodynamic heating requirements, and most importantly, detailed viscous effects (including boundary layer transition). It is the inclusion of detailed viscous effects within the optimization process that makes the present work unique. Optimization is performed using a numerical non-linear minimization algorithm.; As a result of including viscous effects within the optimization process, hypersonic waverider configurations have been designed that look drastically different than previously designed inviscid waveriders, and whose L/D performance break the "L/D barrier" by a significant margin. Due to the inclusion of most of the important physical effects in the aerodynamic analysis of these waveriders, they are expected to perform as predicted in a real flight environment.