It is interesting to note, though, that some of the analysis methods used in CFD predate the computer. In 1929 Prandtl and Busemann applied the method of characteristics using a graphical technique to design a twodimensional supersonic nozzle. A few years later they designed a nozzle for the first practical supersonic wind tunnel (Anderson, 1982). Not sur­ prisingly, though, the real growth of CFD as a practical way of solving real-world problems began with the introduction of the digital computer in about the mid-1960s.