Aerodynamics

distance travelled during a unit of time by a sound wave propagating through an elastic medium

machine with spinning blades used to create airflow

300px|thumb|upright=1.6|A NASA wake turbulence study at Wallops Island in 1990. A [[vortex is created by passage of an aircraft wing, revealed by smoke. Vortices are one of the many phenomena associated with the study of aerodynamics.]]

device that converts wind energy into electrical energy

When two fluid layers move relative to each other, a friction force develops between them and the slower layer acts to slow down the faster layer. This internal resistance to flow is described by the fluid property called viscosity, which reflects the internal stickiness of the fluid. In liquids, viscosity arises from cohesive molecular forces, while in gases it results from molecular collisions. Except for the case of superfluidity, there is no fluid with zero viscosity, and thus all fluid flows involve viscous effects to some degree.

reaction engine which generates thrust by jet propulsion

thumb|right|Two different planforms are shown with a swept wing [[KC-10 Extender (top) refueling a diamond-like delta wing F-22 Raptor]]

thumb|Bird flight by a [[brown pelican.]] thumb|Human-engineered flight: a United Airlines [[Boeing 787 taking off from Heathrow Airport in December 2013.]]

ratio of speed of object moving through fluid and speed of sound

dimensionless quantity that is used to help predict similar flow patterns in different fluid flow situations

reference values for temperature and pressure

important law of classical magnetism

force; aerodynamics term

In fluid dynamics, turbulence or turbulent flow is fluid motion exhibiting chaotic changes in pressure and flow velocity. It is in contrast to laminar flow, which occurs when a fluid flows in parallel layers with no disruption between those layers.

subdiscipline of fluid mechanics that deals with fluid flow—the natural science of fluids (liquids and gases) in motion

flow where fluid particles follow smooth paths in layers

speed that exceeds the speed of sound

system of nonlinear partial differential equations describing the motion of viscous fluids

tool used to study the effects of air moving past solid objects

thumb|Vortex created by the passage of an wing|aircraft wing, revealed by colored smoke thumb|249x249px|Kármán vortex street|Von Kármán vortex street behind a drinking straw; milk was poured into the water to make the current visible thumb|right|250px|A Kármán vortex street is shown in this photo, as winds from the west blow onto clouds that have formed over the mountains in the desert. This phenomenon observed from ground level is extremely rare, as most cloud-related Kármán vortex street activity is viewed from space.

thumb| A hot air balloon produced through the application of Aerostatic principles A subfield of fluid statics, aerostatics is the study of gases that are not in motion with respect to the coordinate system in which they are considered. The corresponding study of gases in motion is called aerodynamics.

thumb|350px|Examples of airfoils in nature, aircraft (ULM=ultra-light), jet engine, and sailing boat The dolphin flipper works in the same way in water and is an example of a hydrofoil. thumb|Streamlines past an airfoil made visible with smoke in a wind tunnel

speed that is faster than Mach 5

difference in wind speed or direction over a short distance

tendency of a fluid jet to stay attached to a convex surface

large system of rotating ocean currents

the reduced aerodynamic drag that an aircraft's wings generate when they are close to a fixed surface

prociple directions in aviation

repeating pattern of swirling vortices caused by the unsteady separation of flow of a fluid around blunt bodies

thumb|250px|right|Three different styles of front wings from three different Formula One eras, all designed to produce downforce at the front end of the respective race cars. Top to bottom: [[Ferrari 312T4 (1979), Lotus 79 (1978), McLaren MP4/11 (1996)]]

Transonic (or transsonic) flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object. The exact range of speeds depends on the object's critical Mach number, but transonic flow is seen at flight speeds close to the speed of sound (343 m/s at sea level), typically between Mach 0.8 and 1.2.

turbulence without visual cues

thumb|NASA testing a scale model Lockheed L-188 Electra|Lockheed Electra in a wind tunnel for flutter

maximum density altitude an aircraft is specified to reach

thumb|right|An airspeed indicator is a [[flight instrument that displays airspeed. This airspeed indicator has standardized markings for a multiengine airplane.]] thumb|Aircraft have pitot tubes for measuring airspeed.

Aeromechanics is a branch of continuum mechanics that deals with the motion of air and other gases and their effects on bodies in the flow, involving aerodynamics, thermophysics and aerostatics. The fluid flow and structure are interactive systems and their interaction is dynamic. The fluid force causes the structure to deform which changes its orientation to the flow and hence the resulting fluid force.

wave pattern in supersonic exhaust

physical measure of overcoming air resistance

sideways nose angle of an aircraft relative to the oncoming airflow or relative wind

coefficient that relates the lift generated by a lifting body to other parameters

type of rotation configuration for helicopter rotor blades

3D generalization of the Leibniz integral rule

the point at which a sudden drop in air pressure occurs

wind tunnel which moves air up in a vertical column

branch of fluid mechanics

high-altitude flying turbine for generating electricity

thumb|In a crosswind landing, the fuselage of the plane may be skewed relative to the runway

higher temperatures due to movement through air

study of road vehicles aerodynamics

behavior of projectiles in flight

flight below 90 kilometres at speeds above Mach 5

400px|thumb|right|A diagrammatic representation of a fixed-wing airplane in phugoid

thumb | rightAeroacoustics is a branch of acoustics that studies noise generation via either turbulent fluid motion or aerodynamic forces interacting with surfaces. Noise generation can also be associated with periodically varying flows. A notable example of this phenomenon is the Aeolian tones produced by wind blowing over fixed objects.

early system for lateral control of a fixed-wing aircraft

thumb|Kammback on a 1969 Fiat 850 Coupe

thumb|right|Grob G 102 Astir prototype with turbulator tape under the wing A turbulator is a device that turns a laminar boundary layer into a turbulent boundary layer.

the science of aircraft and spacecraft design

pressure in the absence of sound waves

French public establishment specializing in aerodynamic studies