The Design, Analysis and Performance Evaluation of Waverider Configurations for Hypersonic Vehicle Applications

Methodologies required for the creation of hypersonic aircraft configurations based on the waverider concept were developed and validated. The design space for these configurations was formulated by using an algorithm that coupled the directional derivatives to the conservation laws and used to generate flow fields in the form of organized sets of stream-surfaces. In general, the design space generated waverider configurations with sharp leading edges. Consequently, a carving methodology was developed and implemented to transform the idealized waverider geometries into practical aircraft configurations with blunted leading edges. Further, methodologies, based on both empirical and analytical relations, were developed and applied with the goal of evaluating the aerothermo-dynamic performance of the resulting hypersonic aircraft configurations. In this effort, methodologies to determine the local pressure, skin-friction and heat flux were also developed, implemented and validated. For example, in regions where the surfaces of vehicle configuration allow for the use of planar models, the flat plate viscous relations for compressible flow were used. However, in other regions, such as, the blunted leading edges, flat plate viscous relations are not applicable, and in those regions the modified Newtonian theory, Fay-Riddell theory and Modified Reynolds analogy were applied. At every stage of this newly develop methodology, the design and analysis routines were validated by either using existing analytical solutions, empirical relationships or independent computer simulation. For example, the set of streamlines that represents the inversely created hypersonic flow field were compared to Taylor-Maccoll exact solution. Similarly, the observed relationships between the local Stanton number and the skin friction coefficient with the local Reynolds number along the ‘slow varying’ regions of the vehicle surface compared extremely well to that of experimental findings. Of particular importance to this effort is the creation of an automated grid generation routine. For the purposes of independent CFD simulations, structured mesh, orthogonal to both the vehicle surface and the freestream, can be generated around the resulting hypersonic vehicle configuration. Based on users’ requirements the grid information is exported to appropriate CFD codes in their respective format. The efficacy of the grid generation technique and the capability of the hypersonic vehicle tool were analyzed. Overall, the independent simulations compared well with the data predicted by the tool. In external flow field comparisons, both approaches; the independent CFD simulations and the vehicle design tool, recovered the exact solution described by the Taylor-Maccoll solution. In addition, the pressure distribution on the vehicle surface compares extremely well to CFD predictions. However, the distribution of the viscous-related surface properties left a bit more to be desired.