Aerospace plane design challenge - Credible computations

Computational fluid dynamics (CFD) is necessary in the design processes of all current aerospace plane programs. Single-stage-to-orbit (SSTO) aerospace planes with air-breathing supersonic and hypersonic combustion are going to be largely designed by means of CFD. The principal challenge of the aerospace plane design is to provide credible CFD results to work from, to assess the risk associated with the use of those results, and to certify CFD codes that produce credible results. CFD uncertainties, credibility requirement, a guide for establishing credibility, and responsibility for credibility are discussed in order to establish the credibility of CFD results used in design. Quantification of CFD uncertainties helps to assess success risks and safety risks, and the development of CFD as a design tool requires code certification. This credibility challenge is managed by "designing" the designers to use CFD effectively, by teaming the computational fluid dynamicists with the designers, by ensuring continuous enhancement of credibility, and by balancing the design process to achieve a judicious balance of computations and measurements.