AERODYNAMICS

Question 1

When a fluid is in motion, it must move
in such a way that mass is conserved.

Answer 1

CONTINUITY EQUATION

Question 2

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

Answer 2

CONTINUITY EQUATION

Question 3

Sound waves travel through the air at a
definite speed.

Answer 3

SPEED OF SOUND

Question 4

This is obvious from natural observation;

Answer 4

SPEED OF SOUND

Question 5

The ____________ in a perfect gas
depends only on the temperature of the
gas.

Answer 5

SPEED OF SOUND

Question 6

It is a function of the temperature.

Answer 6

SPEED OF SOUND

Question 7

It is the flow velocity divided by the speed of sound.

Answer 7

MACH NUMBER

Question 8

Mach number Named after ____________.

Answer 8

ERNST MACH

Question 9

FLOW IN WHICH THE DENSITY OF THE
FLUID ELEMENTS CAN CHANGE FROM
POINT TO POINT.

Answer 9

COMPRESSIBLE FLOW

Question 10

MEANING THE DENSITY AT POINT 1 IS
NOT EQUAL TO THE DENSITY AT POINT
2.

Answer 10

COMPRESSIBLE FLOW

Question 11

STRICTLY SPEAKING, ALL REAL-LIFE
FLOWS ARE COMPRESSIBLE. THERE
ARE CASES WHERE THE DENSITY
CHANGES ONLY SLIGHTLY

Answer 11

COMPRESSIBLE FLOW

Question 12

FLOW IN WHICH THE DENSITY OF THE
FLUID ELEMENTS IS ALWAYS CONSTANT.

Answer 12

INCOMPRESSIBLE FLOW

Question 13

HOWEVER, FOR THOSE FLOWS IN
WHICH THE CHANGE IN DENSITY IS
SMALL, IT IS CONVENIENT TO ASSUME
THAT ρ (RHO) IS CONSTANT.

Answer 13

INCOMPRESSIBLE FLOW

Question 14

IT MEANS DENSITY IS CONSTANT ALONG THE FLOW.

Answer 14

INCOMPRESSIBLE

Question 15

IT MEANS DENSITY IS NOT CONSTANT ALONG THE FLOW.

Answer 15

COMPRESSIBLE

Question 16

THIS EQUATION STATES THAT AN
INCREASE IN VELOCITY LEADS TO AN
DECREASE IN PRESSURE.

Answer 16

BERNOULLI’S EQUATION

Question 17

THE HIGHER THE VELOCITY OF THE FLOW, THE LOWER THE PRESSURE.

Answer 17

BERNOULLI’S EQUATION

Question 18

IT IS THE LOWERING OF FLUID PRESSURE IN
REGIONS WHERE THE FLOW VELOCITY IS INCREASED.

Answer 18

BERNOULLI EFFECT

Question 19

They are large tubes with air moving inside.

Answer 19

WIND TUNNELS

Question 20

They are used to copy the actions of an object in flight.

Answer 20

TUNNELS

Question 21

They use wind tunnels to learn more about how an aircraft will fly.

Answer 21

RESEARCHERS

Question 22

It is a device for testing aircraft and its components in a controlled airstream under
laboratory conditions.

Answer 22

WIND TUNNELS

Question 23

They put a model of an airplane in the tunnel and then study the way air moves around the model.

Answer 23

SCIENTISTS AND ENGINEERS

Question 24

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.

Answer 24

WIND TUNNELS

Question 25

They use wind tunnels to test models of proposed aircraft.

Answer 25

AERODYNAMICISTS

Question 26

They are used for operations at very low Mach Number, with speeds in the test section up to 400 km/h

Answer 26

LOW-SPEED WIND TUNNELS

Question 27

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.

Answer 27

TRANSONIC WIND TUNNELS

Question 28

It should produce supersonic speeds (Mach numbers up to 5)

Answer 28

SUPERSONIC WIND TUNNELS

Question 29

It achieved with an appropriate design of a convergent-divergent nozzle.

Answer 29

SUPERSONIC WIND TUNNELS

Question 30

It is designed to generate a hypersonic flow field in the working section.

Answer 30

HYPERSONIC WIND TUNNELS

Question 31

The speed of these tunnels varies from Mach 5 to 15.

Answer 31

HYPERSONIC WIND TUNNELS

Question 32

These types of tunnels must run intermittently with very high-pressure ratios when initializing.

Answer 32

HYPERSONIC WIND TUNNELS

Question 33

In subsonic wind tunnels, a convenient way of measuring the pressure difference (P1-P2) is by means of _______________.

Answer 33

MANOMETER

Question 34

It is a measure of the purely random motion of molecules in the gas.

Answer 34

STATIC PRESSURE

Question 35

It is due simply to the random motion of the molecules.

Answer 35

STATIC PRESSURE

Question 36

It can also be the pressure of the air around the aircraft at a certain point.

Answer 36

STATIC PRESSURE

Question 37

It is related to the velocity of the air.

Answer 37

DYNAMIC PRESSURE

Question 38

It represents the kinetic energy per unit volume of a fluid due to its motion.

Answer 38

DYNAMIC PRESSURE

Question 39

It is the measure of the impact pressure or “ram air” pressure caused by the forward motion of the aircraft through the air.

Answer 39

DYNAMIC PRESSURE

Question 40

It is the sum of the free-stream dynamic pressure and free-stream static pressure.

Answer 40

TOTAL PRESSURE

Question 41

At a ___________, the fluid velocity is zero.

Answer 41

STAGNATION POINT

Question 42

In the case where the fluid is not moving, _____________ is also the same as the static pressure.

Answer 42

TOTAL PRESSURE

Question 43

The pitot tube was invented by a Frenchman, named _______________.

Answer 43

HENRI PITOT

Question 44

It is an instrument that measures the total pressure at a point in the flow.

Answer 44

PITOT TUBE

Question 45

It is most often a flush-mounted hole on the fuselage of an aircraft.

Answer 45

STATIC PORTS

Question 46

It is obtained through a static port.

Answer 46

STATIC PRESSURE

Question 47

It is a system of pressure-sensitive instruments that is most often used in aviation.

Answer 47

PITOT-STATIC SYSTEM

Question 48

It consists of a pitot tube, a static port, and the pitot-static instruments.

Answer 48

PITOT-STATIC SYSTEM