Review of gaps, obstacles, and technological challenges in hypersonic applications (Gotchas)

In this study, the extensive hypersonic literature is canvassed for the purpose of identifying and compiling a list of gaps, obstacles, and technological challenges in hypersonic applications (GOTCHAs). The significance of GOTCHA-related deficiencies is discussed along with potential solutions, promising methodologies, and feasible remedies that may be considered by engineers in pursuit of next-generation hypersonic vehicle designs and optimizations. Based on the synthesis of several modern surveys and public reports, a cohesive list is formed consisting of widely accepted areas needing improvement under several general categories. These include: aerodynamics, propulsion, materials, analytical modeling, computational fluid dynamics modeling, and education in high-speed flow physics. New methods and lines of research inquiry are suggested such as homotopy-based analysis for the treatment of strong nonlinearities, the use of improved turbulence models and unstructured grids in numerical simulations, the need for accessible validation data, and the refinement of mission objectives for hypersonic airbreathing propulsion.