Progress and future prospects of CFD in aerospace - Wind tunnel and beyond

A historical perspective of computational fluid dynamics (CFD) in aerospace in the last 30 years is firstly given. It is shown that there still remain a number of problems that are geometrically simple but difficult to simulate even after many simulations were conducted over complex body configurations. The fact indicates that CFD research is now in the "specific phase" and requires some innovation. The innovation includes "evolutionary effort" and "revolutionary effort". As an example of evolutionary effort, large eddy simulations/ Reynolds-averaged Navier-Stokes simulations (LES/RANS) hybrid method and its application examples are presented. A shift from RANS to LES/RANS hybrid method occurs not because of the advancement of computers but because of our recognition that separated flows are inherently unsteady and successful simulations require LES-like computations. Comment is given that there may be other types of research necessary to make CFD a real useful tool for a design in addition to simply showing CFD capability for complex body configurations. As one of the examples, construction of a CFD database is presented. Another issue is to make CFD infrastructures so that people outside CFD community may use CFD as a tool to formulate or refine their ideas. To find out revolutionary effort, the message given by Prof. Dean Chapman in 1977 is referred. Observation of current CFD research reveals that evaluation methods of "scale effect" that were believed to be the most important benefit of CFD have not yet been established. Such establishment is the key for the revolution of CFD and researchers need to focus their effort on the development of technologies to evaluate scale effect. Only with such new CFD technologies can "conceptual design with CFD" become feasible. (c) 2005 Elsevier Ltd. All rights reserved.