Aerodynamics Topics

Ablating Nose Cone

A nose cone designed to reduce heat transfer to the internal structure by the use of an ablating material.

Absolute Ceiling

The maximum altitude above sea level at which a heavier-than-air craft can be maintained in level flight.

Absolute Vorticity

The vorticity of a fluid particle expressed with respect to an absolute coordinate system.

Aerobatics

Voluntary manoeuvres, initiated by a pilot, other than those for conventional flight.

Aerodynamic Diameter

The diameter of a sphere with unit density that has aerodynamic behavior identical to that of the particle in question.

Aerodynamic Drag

Resistance of a vehicle body to motion through the air. A smooth surface has less drag than a rough one.

Aerodynamic Force

The force exerted by a moving gaseous fluid upon a body completely immersed in it.

Aerodynamic Heating

The heating of a body produced by passage of air or other gases over the body.

Aerodynamic Noise

Sound generated by turbulent flow is just as if the field were generated by a distribution of quadrupole sources.

Aerodynamic Trail

A condensation trail formed by adiabatic cooling to saturation of air passing over the surfaces of high-speed aircraft.

Aerodynamic Vehicle

A device, such as an airplane, glider, etc., capable of flight only within a sensible atmosphere and relying on aerodynamic forces to maintain flight.

Aeroelasticity

Any phenomenon which includes the mutual interaction between aerodynamic loads and structural deformation.

Aerofoil

An aerofoil is shaped so that air flows faster over the top than under the bottom. There is, therefore, a greater pressure below the aerofoil than above it. This difference in pressure produces the lift.

Aeronautics

The term "aeronautics" originated in France, and was derived from the Greek words for "air" and "to sail".

Aeropause

A region of indeterminate limits in the upper atmosphere, considered as a boundary or transition region between the denser portion of the atmosphere and space.

Aerostat

Denotes a lighter than air craft.

Aerothermodynamic

A branch of thermodynamics relating to the heating effects associated with the dynamics of a gas.

Aerothermodynamic Border

An altitude at about 100 miles, above which the atmosphere is so rarefied that the skin of an object moving through it at high speeds generates no significant heat.

Aerothermoelasticity

The study of the response of elastic structures to the combined effect of aerodynamic heating and loading.

Aileron

These are situated on the trailing (back) edge of the wing and are used to make the aircraft roll.

Airbrake

An aerodynamic control which can be extended to increase drag and slow down an aircraft.

Aircraft

Any structure, machine, or contrivance, especially a vehicle, designed to be supported by the air.

Airflow

A flow or stream of air.

Airframe

The structure of an aircraft, without power plant and systems.

Airship

A powered lighter-than-air craft.

Airspeed

The speed of something relative to a mass of air or the speed of air relative to a fixed object.

Angle of Attack

The angle at which a wing strikes the air stream.

Atmospheric Boundary Layer

The atmospheric layer adjacent to the surface of the Earth that is affected by friction against the surface boundary.

Autogyro

An aeroplane that flies by virtue of the lift generated by freewheeling rotating wings set windmill fashion above the fuselage.

Balloon

A lighter than air craft. The Montgolfier brothers made the first flight in a hot air balloon in 1783.

Ballute

A cross between a balloon and a parachute, used to brake the free fall of sounding rockets.

Biplane

An airplane with two sets of wings, one on top of the other.

Boost Pressure

The increase above atmospheric pressure produced inside the intake manifold by a forced-induction system such as a turbocharger or supercharger.

CAA

Abbreviation of Civil Aviation Authority.

Canard

A horizontal pitch control surface on an aircraft that is forward of the main wing.

Ceiling

The overhead upper surface.

Centre of Pressure

The point at which the aerodynamic forces on a body appear to act, and at which there is no aerodynamic movement.

Chord

A line segment that connects two points of a curve or circle.

Civil Aviation Authority

The UK′s independent specialist aviation regulator. Its activities include economic regulation, airspace policy, safety regulation and consumer protection.

Compressible Fluids

Compressible flow requires the integration of the equations of conservation of mass and momentum with that of energy conservation.

Cowling

The name of the fairing which, usually, encloses an engine on an aeroplane.

Crosswind

Any wind that is blowing perpendicular to a line of travel.

Delta Wing

An aircraft wing that when viewed in plan has the shape of an isosceles triangle.

Dihedral

Angle which the spanwise axis of an aerofoil makes to the fuselage when the wing or tailplane tip is higher than its root attachment point.

Drag

Resistance of a vehicle body to motion through the air. A smooth surface has less drag than a rough one.

Drag Coefficient

A dimensionless value that allows the comparison of shape and orientation of different bodies.

Drogue Parachute

Parachute attached to a body, used to slow it down.

Dynamic Sealing

Vehicle door seals must function when the aerodynamic load on the door pulls the door away from the seals.

Elevator

Movable control surface, attached to the trailing edge of an aircraft tailplane to control pitching movements.

Elevon

Movable control surfaces which act collectively as elevators, but differentially as ailerons.

Flaps

Hinged surfaces normally located at the trailing edge of the wing designed to increase the wings lift and the slow-flight characteristics.

Flight Controls

Moveable surfaces on the aircraft that control its path through the air.

Flow Noise

A term generally used to describe aerodynamic noise produced when a gas flows within a duct or when the gas exits the duct.

Flow Rate

Volume per unit of time.

Fuselage

The main body of the aircraft.

Glider

A highly efficient engineless aeroplane. Capable of flying for long periods in gently rising air currents.

Helicopter

An aircraft that produces lift using airfoils that are driven and rotate about a vertical axis.

Kinematic Viscosity

The dynamic viscosity of a fluid divided by the fluid density.

Kinetic Heating

Heating as a result of air friction.

Knudsen Flow

The flow of gases through ducts and tubes under conditions intermediate between laminar viscous flow and molecular flow.

Laminar Flow

Smooth flow in which no crossflow of fluid particles occur between adjacent streamlines, a flow conceived as made up of layers.

Leading Edge

The edge of an airfoil which first meets the airstream in normal flight.

Lift

The lifting force on a flying object.

Lift Coefficient

A dimensionless value that allows the comparison of lift incurred by different sized and different shaped bodies. A positive lift coefficient represents lift, whilst a negative lift coefficient represents downforce.

Lifting Body

An aircraft that uses the shape of its body to generate lift instead of using wings.

Mass Flow Rate

Defines the volumetric rate with which fluids flow, maintaining the equation of continuity.

Monoplane

An aircraft with one set of wings.

Orifice

Accurate size opening for controlling fluid flow.

Parachute

Used to decelerate an object.

Pitot Tube

An open ended tube arrangement to face against the current of a stream of fluid used in measuring the velocity head of a flowing medium.

Poiseuilles Equation

Gives the volume flow rate of an incompressible fluid in a round pipe.

Pressure

Defined as the force exerted per unit area.

Pressure Coefficient

A dimensionless value which acts as a means of indicating the local pressure at some point of interest around a body, and which is independent of velocity.

Profile Drag

This is drag from the three-dimensional shape of the aircraft or vehicle.

Ram Air

Air entering an air inlet as a result of the high-speed forward movement.

Reyn

British unit of dynamic viscosity.

Rudder

The moving part of the vertical tail surface of an aeroplane which provides yaw control or the device in the water on a boat that provides directional control.

Service Drag

This is drag from air ducted to cooling components.

Transonic

Speeds slightly above and below the speed of sound.

Triplane

A fixed wing aeroplane with 3 wings arranged one above the other.

Turbulent Flow

Fluid motion in which random motions of parts of the fluid are superimposed upon a simple pattern of flow.

Velocity Pressure

The difference between dynamic pressure and static pressure.

Viscosity

A measure of the internal friction within a fluid.

Viscous Flow

The flow of fluid through a duct under conditions such that the mean free path is very small in comparison with the smallest dimension of a transverse section of the duct.

Vorticity

A vector measure of local rotation in a fluid flow, defined mathematically as the curl of the velocity vector.

Vorticity Equation

A dynamic equation for the rate of change of the vorticity of a parcel, obtained by taking the curl of the vector equation of motion.

Wind Axis

Any one of a system of mutually perpendicular reference axis established with respect to the undisturbed wind direction about an aircraft or similar body.

Wind Tunnel

A tunnel with a large fan that is used by engineers to test the effects of high winds on a structure.

Wind Tunnel Balance

A device or apparatus that measures the aerodynamic forces and moments acting upon a body tested in a wind tunnel.

Wing Warping

The earliest form of roll control was produced by warping the whole wing.

Zero-Lift Chord

A chord taken through the trailing edge of an airfoil in the direction of the relative wind when the airfoil is at a zero-lift angle of attack.