The role of computational fluid dynamics in aeronautical engineering

Some of the available methods in actual design and the trend in computational fluid dynamics (CFD) are presented. Inviscid linear flow, the panel method and the vortex lattice method are the only methods for analyzing arbitrary practical configurations and are the most useful engineering tools available. Although these approach a relatively mature level, the improvement required for these methods are: (1) capability of treating more complicated realistic geometries; (2) development of the resources needed to supply the error-free input data; and (3) extension to the free boundary problem such as leading-edge vortex. The inviscid nonlinear flow, the vigorous advance of CFD, especially in the transonic regime, had a strong impact on changing the previous semiempirical design methods to more rational ones and it has shortened the design time and reduced costs. The most promising available codes, which analyze wing-body combinations, are expected to provide the new technological capability of interpreting the various useful design rules. The separated viscous flow, the calculations of Reynold's averaged equations are expected to become effective design tools for evaluating off-design features. It leads to the elimination of oversized margins in design. The three groups of numerical methods are expected to make progress more or less in parallel with each other.