CFD and some of its applications

The CFD codes which can be used in industrial applications are discussed, and it is emphasized that the industrial codes will have to be chosen consistent with the phase of the design. In this paper, a hierarchy of fluid-flow models, in decreasing order of complexity, is obtained by simplifications to the Navier-Stokes (N-S) equations resulting progressively through the neglect of viscosity, rotationality, time-dependence, or less-dominant terms or through linearization or simplification of boundary conditions. The paper highlights the utility of a hierarchy of fluid-flow models and the resulting computer codes in arriving at design information appropriate to different phases of development of aerospace vehicles. Several applications of a possible hierarchy of approximations of N-S equations to practical problems are illustrated based on work carried out at the National Aeronautical Laborator