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.
Aeroballistics
The study of the interaction of projectiles or high speed vehicles with the atmosphere.
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.
Aerodynamics Weblinks
Lists all Aerodynamic Weblinks in the Encyclopaedia
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.
Air Scoop
A forward facing aerodynamic device or opening used to duct cool outside air to some part of the vehicle.
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.
Airspeed
The speed of something relative to a mass of air or the speed of air relative to a fixed object.
Altitude Wind Tunnel
A wind tunnel in which the air pressure, temperature, and humidity can be varied to simulate conditions at different altitudes.
Angle of Attack
The angle at which a wing strikes the air stream.
Angle of Climb
The angle between the flight path of a climbing vehicle and the local horizontal.
Angle of Descent
The angle between the flightpath of a descending vehicle and the local horizontal.
Angle of Roll
The angle that the lateral body axis of an aircraft or similar body makes with a chosen reference plane in rolling; usually the angle between the lateral axis and a horizontal plane.
Anhedral
The angle between an aerofoil and the horizontal when the wing is inclined downwards from its mounting.
Aspect Ratio
For a graphics device it is the ratio of the screen dimensions, normally defined as vertical screen dimension divided by horizontal screen dimension.
Atmospheric Boundary Layer
The atmospheric layer adjacent to the surface of the Earth that is affected by friction against the surface boundary.
Attached Shock Wave
An oblique or conical shock wave that appears to be in contact with the leading edge of an airfoil or the nose of a body in a supersonic flow field.
Aviation
Lists all Aviation topics in the Encyclopaedia
Bernoulli′s Principle
The pressure in a fluid decreases as its velocity increases.
Blowdown Wind Tunnel
An open-circuit wind tunnel in which gas stored under pressure is allowed to expand through a test section to provide a stream of gas or air to test a model.
Boattail
The rear portion of an elongated body, having decreasing cross-sectional area toward the rear.
Boundary Layer
The portion of a fluid flowing past a body that is in the immediate vicinity of the body.
Buffet
Irregular, often violent, oscillations that are the result of unsteady aerodynamic flow around a body.
CAA
Abbreviation of Civil Aviation Authority.
Camber
Generally a curve.
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.
CFD
Abbreviation of Computational Fluid Dynamics.
Chord
A line segment that connects two points of a curve or circle.
Chord Line
A line joining the leading edge to the trailing edge.
Civil Aviation Authority
The UK′s independent specialist aviation regulator. Its activities include economic regulation, airspace policy, safety regulation and consumer protection.
Closed Circuit Wind Tunnel
The outlet is connected to the inlet so that the air circulates around the tunnel.
Collective Pitch Control
Used to change simultaneously the pitch of all of a helicopter rotor′s blades to permit ascent or descent.
Compressible Fluids
Compressible flow requires the integration of the equations of conservation of mass and momentum with that of energy conservation.
Computational Fluid Dynamics
A tool for predicting the aerodynamics and fluid dynamics of air around flight vehicles by solving a set of mathematical equations with a computer.
Condensation Shock Wave
A sheet of discontinuity associated with a sudden condensation and fog formation in a field of flow.
Condensation Trail
A cloud like streamer or trail often seen behind aircraft flying in clear, cold, humid air.
Cowling
The name of the fairing which, usually, encloses an engine on an aeroplane.
Critical Reynolds Number
The point at which some significant change occurs.
Crosswind
Any wind that is blowing perpendicular to a line of travel.
Cyclic Pitch Control
Means of changing the pitch of a rotor′s blades progressively, to provide a horizontal thrust component for flight in any horizontal direction.
Diffuser
The divergent section of a duct which slows down airflow to reduce pressure loss.
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.
Dihedral Angle
The angle formed by two planes meeting in space.
Drag
Resistance of a vehicle body to motion through the air. A smooth surface has less drag than a rough one.
Drag Chute
A heavy-duty parachute attached to a vehicle and is used to rapidly add aerodynamic drag and to reduce the vehicle′s speed.
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 Pressure
The pressure of a fluid resulting from its motion when brought to rest on a surface.
Dynamic Sealing
Vehicle door seals must function when the aerodynamic load on the door pulls the door away from the seals.
Expansion Tube Tunnel
A wind tunnel for conducting tests at hypervelocity.
Fin
A fixed vertical aerodynamic surface or part of a cooling system.
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.
Flutter
Unstable oscillation of an airfoil surface.
Frontal Area
Generally taken to be the area of the front view silhouette of a vehicle, though sometimes simplified as width multiplied by height.
Glide Ratio
The ratio of the horizontal distance traveled to the vertical distance descended in a glide.
Glider
A highly efficient engineless aeroplane. Capable of flying for long periods in gently rising air currents.
Ground Effect
The aerodynamic modification of the airflow beneath a vehicle caused by its close proximity to the ground.
Impact Pressure
Another name for Dynamic Pressure.
Intermittent Wind Tunnel
A wind tunnel in which energy is stored, usually as compressed air, and then released suddenly to force a large quantity of air through.
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.
Magnus Effect
A rotating cylinder in a moving fluid drags some of the fluid around with it, in its direction of rotation. This increases the speed in that region, and thus the pressure is lower generating a net force on the cylinder in that direction, perpendicular to the flow of the fluid.
Mass Flow Rate
Defines the volumetric rate with which fluids flow, maintaining the equation of continuity.
Moving Ground Plane Wind Tunnel
A wind tunnel with a system that allows the floor to be moved relative to the test object and matched in speed to the bulk air flow.
NACA Duct
A distinctively shaped inlet that is flush and begins with a narrow, shallow inset and becomes progressively wider and deeper.
Orifice
Accurate size opening for controlling fluid flow.
Parabrake
Deceleration parachute.
Parachute
Used to decelerate an object.
Piston Driven Wind Tunnel
A type of shock tunnel in which energy is created by a piston being fired or driven down a cylinder.
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.
Propeller
An assembly of radially disposed blades with an airfoil shape that when rotated in air produce thrust.
Ram Air
Air entering an air inlet as a result of the high-speed forward movement.
Ram-Rocket
A rocket engine in which an air-breathing inlet and duct system are added, permitting atmospheric air to be introduced at the exit of the rocket combustion chamber.
Reyn
British unit of dynamic viscosity.
Sail Wing
A propeller having cloth stretched over a metal wire frame which forms an airfoil section.
Service Drag
This is drag from air ducted to cooling components.
Shock Tunnel
A hypervelocity wind tunnel.
Shock Wave
The characteristic cone-shaped wave front that is produced whenever an object travels faster than the speed of the waves in the surrounding medium.
Stagnation Pressure
Another name for Dynamic Pressure.
Stall
Condition which arises when the smooth airflow over a wing′s upper surface breaks down and its lift is destroyed.
Streamlined
Having a smooth even shape that offers the least resistance to movement through the air.
Suckdown Wind Tunnel
The inlet is open to atmosphere and the fan is placed after the test section.
Thrust Vectoring
Using a directional rocket nozzle to guide flight.
Tip Speed Ratio
Ratio of the propeller tip speed to the wind speed.
Total Pressure
Another name for Dynamic Pressure.
Transition Point
The point of change from laminar to turbulent flow.
Transonic
Speeds slightly above and below the speed of sound.
Turbulence
Describes fluid motion disturbed from its average behaviour by random fluctuations over a range of temporal and spatial scales.
Turbulent Boundary Layer
Within this layer the Reynolds stresses are much larger than the viscous stresses.
Turbulent Flow
Fluid motion in which random motions of parts of the fluid are superimposed upon a simple pattern of flow.
U-Tube Manometer
Device for measuring pressure.
Vanes
Baffles employed to deflect the flow of a fluid, gas or liquid.
Vehicle Aerodynamic Drag
Resistance of a vehicle body to motion through the air.
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.
Windage Loss
The power absorbed by the fluid surrounding a rotating body.
Wing
A surface that has an airfoil cross-section and is used to generate lift.
Yaw Axis
A vertical axis through an aircraft, rocket, or similar body, about which the body yaws.
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.

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Subjects: Automotive Mechanical Engineering Physics