Basic concepts and definitions

Preamble

The study of aerodynamics, as is the case with that of all physical sciences and technologies, requires the common acceptance of a number of basic definitions including an unambiguous nomenclature and an understanding of the relevant physical properties, the related mechanics and the appropriate mathematics.

Of course, many of these are common to other disciplines and it is the purpose of this chapter to identify and explain those that are basic and pertinent to aerodynamics and which are to be used in the remainder of the volume.

The units and dimensions of all physical properties and the relevant properties of fluids are recalled, and after a review of the aeronautical definitions of wing and aerofoil geometry, the remainder of the chapter introduces aerodynamic force.

The origins of aerodynamic force and how it is manifest on wings and other aeronautical bodies and the theories that permit its evaluation and design are to be found in the remainder of the volume, but in this chapter the lift, drag, side-wind components and associated moments of aerodynamic force are conventionally identified, the application of dimensional theory establishing their coefficient form. The significance of the pressure distribution around an aero­dynamic body and the estimation of lift, drag and pitching moment on it in flight, completes this chapter of basic concepts and definitions.