Flow classification[ edit ] Flow velocity is used to classify flows according to speed regime. Building on these developments as well as research carried out in their own wind tunnel, the Wright brothers flew the first powered airplane on December 17, Compressible flow accounts for varying density within the flow.
This difference most obviously manifests itself in the case of a fluid striking an object. Of these, lift and drag are aerodynamic forces, i.
Main article: History of aerodynamics Modern aerodynamics only dates back to the seventeenth century, but aerodynamic forces have been harnessed by humans for thousands of years in sailboats and windmills,  and images and stories of flight appear throughout recorded history,  such as the Ancient Greek legend of Icarus and Daedalus.
Effects of compressibility are more significant at speeds close to or above the speed of sound. Density, flow velocity, and an additional property, viscosityare used to classify flow fields.
During the time of the first flights, Frederick W. Further information: incompressible flow An incompressible flow is a flow in which density is constant in both time and space.
Conservation laws[ edit ] The assumption of a fluid continuum allows problems in aerodynamics to be solved using fluid dynamics conservation laws.
Internal aerodynamics is the study of flow through passages in solid objects.