25-08-2017, 09:32 PM
PRINCIPLES OF FLIGHT
PRINCIPLES OF FLIGHT.ppt (Size: 519 KB / Downloads: 65)
DEFINITIONS
Mass :- Mass is the quantity of matter in a body
Density :- Density is the mass per unit volume.
Pressure :- Pressure is the force per unit area. (Units:- lbs / sq inch)
Momentum :- The quantity of motion in a body is known as momentum of the body and is equal to the product of mass and velocity (M = m x v)
Motion :- When a body changes its position in relation to its surroundings.
Speed :- Speed is the rate of change of position.
Velocity :- Velocity is the speed in a particular direction. Velocity is a vector quantity having both magnitude and direction.
Acceleration :- Acceleration is the rate of change of velocity.
Boyles’ Law :- The volume of a given mass of a perfect gas is inversely proportional to the pressure, provided the temperature remains constant. p x v = constant (temp unchanged)
Charles’ Law :- The volume of a perfect gas increases by 1/273 of its value at 0°C for every degree C rise in temperature, provided the pressure remains constant.
Laws Of Motion
Newton’s First Law Of Motion :
A body which is in a state of rest or of its uniform motion will continue to be in the same state unless an external force is applied upon it. This property of all bodies is called inertia and a body in such a state is said to be in equilibrium.
Introduction :-
The word Atmosphere is derived from the Greek ‘Atoms’ means ‘vapour’ and ‘phere’ means ‘sphere’.
Atmosphere means the gaseous sphere surrounding the earth.
Temperature :-
The temperature of earth’s surface depends almost entirely upon the heat received from the sun. As a rule, temperature decreases with height. The hotter the earth’s surface becomes, more readily it radiates its heat back again to space.
Heat is transferred by three methods i.e. (i) Conduction (ii) Convection and (iii) Radiation
The instrument used for measuring temperature is called thermometer and the units of measure is either “Fahrenheit” or “Centigrade” in degrees.
Bernauli’s Theorem :-
In the early days of the Industrial revolution, Daniel Bernauli, an Italian physicist, discovered certain properties relating to fluids in motion, which he summarized as follows:-
The total energy in a moving fluid is the total sum of three forms of energy i.e. Potential, Kinetic and Pressure Energy.
In a stream line flow of an ideal fluid, the sum of all these three energies remains constant.
Venturi effect and Bernauli’s Theorem :-
In the previous chapter, we have seen that for a flow of air to remain streamlined, the volume passing at a given point in unit time’ must remain constant.
If a venturi tube is placed in such an air stream, then the mass flow in the venturi tube must also remain constant and streamlined.
In order to achieve this and still pass through the restricted section of the venturi, and accompanying pressure drop is a natural consequence according to Bernauli’s theorem.