ABSTRACT
This chapter deals with some steady two-dimensional and three-dimensional ¡ow problems, both supersonic and subsonic. The governing equations are ‡rst established for irrotational motion, and then solutions to these equations are sought. The Janzen-Rayleigh expansion is discussed ‡rst. This expansion is a parameter expansion in powers of the Mach number squared, and so it is valid only for Mach numbers that are somewhat less than unity. Small-perturbation theory is next discussed. This approximation assumes that the body about which the ¡ow is sought disturbs the free stream in a minor way only. Since many real ¡ow situations satisfy this condition, smallperturbation theory is widely used.
