AERODYNAMICS Flashcards
When a fluid is in motion, it must move
in such a way that mass is conserved.
CONTINUITY EQUATION
As long as the flow is steady, the mass
that flows through the cross-section at
point 1 must be the same as the mass
that flows through the cross section at
point 2
CONTINUITY EQUATION
Sound waves travel through the air at a
definite speed.
SPEED OF SOUND
This is obvious from natural observation;
SPEED OF SOUND
The ____________ in a perfect gas
depends only on the temperature of the
gas.
SPEED OF SOUND
It is a function of the temperature.
SPEED OF SOUND
It is the flow velocity divided by the speed of sound.
MACH NUMBER
Mach number Named after ____________.
ERNST MACH
FLOW IN WHICH THE DENSITY OF THE
FLUID ELEMENTS CAN CHANGE FROM
POINT TO POINT.
COMPRESSIBLE FLOW
MEANING THE DENSITY AT POINT 1 IS
NOT EQUAL TO THE DENSITY AT POINT
2.
COMPRESSIBLE FLOW
STRICTLY SPEAKING, ALL REAL-LIFE
FLOWS ARE COMPRESSIBLE. THERE
ARE CASES WHERE THE DENSITY
CHANGES ONLY SLIGHTLY
COMPRESSIBLE FLOW
FLOW IN WHICH THE DENSITY OF THE
FLUID ELEMENTS IS ALWAYS CONSTANT.
INCOMPRESSIBLE FLOW
HOWEVER, FOR THOSE FLOWS IN
WHICH THE CHANGE IN DENSITY IS
SMALL, IT IS CONVENIENT TO ASSUME
THAT ρ (RHO) IS CONSTANT.
INCOMPRESSIBLE FLOW
IT MEANS DENSITY IS CONSTANT ALONG THE FLOW.
INCOMPRESSIBLE
IT MEANS DENSITY IS NOT CONSTANT ALONG THE FLOW.
COMPRESSIBLE
THIS EQUATION STATES THAT AN
INCREASE IN VELOCITY LEADS TO AN
DECREASE IN PRESSURE.
BERNOULLI’S EQUATION
THE HIGHER THE VELOCITY OF THE FLOW, THE LOWER THE PRESSURE.
BERNOULLI’S EQUATION
IT IS THE LOWERING OF FLUID PRESSURE IN
REGIONS WHERE THE FLOW VELOCITY IS INCREASED.
BERNOULLI EFFECT
They are large tubes with air moving inside.
WIND TUNNELS
They are used to copy the actions of an object in flight.
TUNNELS
They use wind tunnels to learn more about how an aircraft will fly.
RESEARCHERS
It is a device for testing aircraft and its components in a controlled airstream under
laboratory conditions.
WIND TUNNELS
They put a model of an airplane in the tunnel and then study the way air moves around the model.
SCIENTISTS AND ENGINEERS
They are usually made out of steel or aluminum, that are tested and loaded with many instruments and sensors that report back to the computers in the control room.
WIND TUNNELS
They use wind tunnels to test models of proposed aircraft.
AERODYNAMICISTS
They are used for operations at very low Mach Number, with speeds in the test section up to 400 km/h
LOW-SPEED WIND TUNNELS
These types of Wind tunnels are able to
achieve speeds close to the speed of sound.
The highest speed is reached in the test
section.
TRANSONIC WIND TUNNELS
It should produce supersonic speeds (Mach numbers up to 5)
SUPERSONIC WIND TUNNELS
It achieved with an appropriate design of a
convergent-divergent nozzle.
SUPERSONIC WIND TUNNELS
It is designed to generate a hypersonic flow field in the working section.
HYPERSONIC WIND TUNNELS
The speed of these tunnels varies from Mach 5 to 15.
HYPERSONIC WIND TUNNELS
These types of tunnels must run intermittently
with very high-pressure ratios when initializing.
HYPERSONIC WIND TUNNELS
In subsonic wind tunnels, a convenient way of measuring the pressure difference (P1-P2) is by means of _______________.
MANOMETER
It is a measure of the purely random motion of molecules in the gas.
STATIC PRESSURE
It is due simply to the random motion of the molecules.
STATIC PRESSURE
It can also be the pressure of the air around the aircraft at a certain point.
STATIC PRESSURE
It is related to the velocity of the air.
DYNAMIC PRESSURE
It represents the kinetic energy per unit volume of a fluid due to its motion.
DYNAMIC PRESSURE
It is the measure of the impact pressure or “ram air” pressure caused by the forward motion
of the aircraft through the air.
DYNAMIC PRESSURE
It is the sum of the free-stream dynamic pressure and free-stream static pressure.
TOTAL PRESSURE
At a ___________, the fluid velocity
is zero.
STAGNATION POINT
In the case where the fluid is not
moving, _____________ is also the same
as the static pressure.
TOTAL PRESSURE
The pitot tube was invented by a
Frenchman, named _______________.
HENRI PITOT
It is an instrument that measures the
total pressure at a point in the flow.
PITOT TUBE
It is most often a flush-mounted hole on the fuselage of an aircraft.
STATIC PORTS
It is obtained through a static port.
STATIC PRESSURE
It is a system of pressure-sensitive instruments that is most often used in aviation.
PITOT-STATIC SYSTEM
It consists of a pitot tube, a static port,
and the pitot-static instruments.
PITOT-STATIC SYSTEM
