Air in Motion

Abstract

Aside from the first two chapters, we are following a sequence of topics that is quite traditional—except for the lack of mathematics—in the multitude of texts discussing fluid mechanics, the basis of aerodynamics. In this chapter we will close our discussion of the underlying science of flight. We have already seen that fluid mechanics teaches the behavior of fluids—liquids and gases—at rest and in motion. Only after mastering these fundamentals, albeit here without the use of higher mathematics, can we begin to understand aerodynamic drag and lift and what makes airplanes fly.

Looking back on fifty years of aerodynamics research during the first half of this century, it appears most remarkable that the crude approximation which considers the air as an incompressible nonviscous fluid proved itself so valuable in solving many problems of practical aircraft design.

Theodore Von Kármán (1881–1963).