2. SUPERSONIC PLANES
Fluid Mechanics 2
Course Seminar
- Teacher: Dr. Hoseinalipour
- TA’s: Mr. Zamani and Mr. Madadelahi
- Presented by: Jahani and Abdolzade
- Springe 2013
4. INTRO
A heavier-than-air machine that is kept aloft by the forces on its wings
Common types of airplanes are airliners, large planes usually used to transport
passengers; military planes; and general-aviation aircraft, which cover all
airplanes that are not airliners or military aircraft
An airplane is thrust forward by a propeller or other means of
propulsion, such as a jet or rocket.
Typical speeds for supersonic aircraft are greater than 750 mph but less than
1500 mph, and the Mach number M is greater than one and less than 3. Above
Mach 5, the term hypersonic is used.
5. HISTORY
Generals
X-1
Concord
Leonardo da Vinci was the first man to attempt the scientific design
of flying machines. But in his time no motor was available which was
powerful enough to lift a person into the air
The first successful controlled airplane flight was made by the
Wright brothers near Kitty Hawk, North Carolina, on December
17, 1903
The first of the X-planes. It was based on thetransport had an ogival delta wing, a
The Concorde supersonic shape
of a .22 caliber bullet, withfuselage and four underslung Rolls-Royce/Snecma Olympus
slender revolutionary thin, straight
wings. The rocket-powered Bell, X-1 only carried to a regular service have been
593 engines. the was SSTs to see
height of about 12,200 meters under Tupolev Tu-144
Concorde and the the belly of a
Boeing B-29 Superfortress before being released
6. INTRODUCTIONS
The branch of physics dealingshockthe flow of air or
loud noise created by the with wave set up by an
other gas around a body in at supersonic speeds.
aircraft or missile traveling motion relative to it.
Aerodynamic forces of booms: N-waves and U-waves. The
There are two types depend on the body's size, shape,
and velocity; The on the density, compressibility, supersonic
and interface that forms between a
N-wave is generated from steady flight conditions, and its
fluid and an obstacle, such as denser medium.
viscosity, wave theory of airplaneletter "N.“aacute angle
pressure temperature, and pressure of the gas.
In the is shaped like the wings, the
Many examples are found in astronomy. A bow
The U-wave, or focused boom, is generated from
between the wing profile (roughly, measured
shock forms at the outermost part of a planetary
maneuvering flights, and its pressure wave is shaped like the
along its bottom) and the wing's motion relative
magnetosphere, where the high-speed flow of
letter
to the surrounding air. "U."
the solar wind is suddenly slowed to subsonic
speed by the planetary magnetic field
The aspect ratio is the square of the
wingspan divided by the platform area of the
wing: AR = b2/S
Mach number
Forces of flight
Aerodynamics
Angle of attack
Aspect ratio
Bow shock
Sonic boom
It is a measure of how long and slender a
wing is from tip to tip
7. MACH NUMBER
Descriptive of something the travels at
A unit of speed, named after that Austrian speeds
greater than Mach equal times the ambient
physicist Ernst Mach, 5 (five to the ratio of the
speed a sound). At such speeds, the
speed of ofmoving object to the speed of sound
temperature in medium under ambient
in the surroundingthe boundary layer and on the
surface
conditions.of the moving vehicle exceeds 1,800°F
(1,000°C) and aerodynamic heating becomes
Flight in the range between the onset of compressibility effects
in aircraft design.
(around Mach number,0.8important and the establishment of fully
M < M, of 0.7)
subsonic
The(around Mach number of 1.4).
V-2 rocket was the first human-made object
supersonic flight conditions
0.8 < M < 1.2
transonic
to achieve hypersonic flight. In February 1949, its
1.2 < Mupper
< 5.0
supersonic
While the aircraft itself may bestage reached a maximum velocity of
traveling less than the speed of
M > 5.0
hypersonic
5,150 mph (8,288 km/h) – speed of sound
sound, the air going around the aircraft exceeds the more than five times
at some locations on thethe speed ofthe regions where the local
aircraft. In sound.
At sea than the speed of sound, known as Mach
airspeed is near or greaterlevel, the speed of sound, compressibility
1.0, and the air miles may vary because of
effects are encounteredis about 761densityper hour (1,225 km/h). At
20,000 ft (6,096 m), the speed
local shock waves, expansions, or flow choking. of sound is 660
mph (1,062 km/h).
Subsonic
Transonic
Supersonic
Hypersonic
8. FORCES
1. (ROCKETRY). The forward force generated by a
rocket. Thrust is produced by the expulsion of a
Drag
reaction mass, such as the hot gas products of a
Thrust
chemical reaction. F = mpve
Lift
2. (AERODYNAMICS). Thrust is also one of the four
forces of flight acting on an aircraft, the others being
weight, drag, and lift. Thrust must be greater than drag
to achieve the forward acceleration needed for takeoff
The lifting force on a flying object (in
and to increase an aircraft's speed in level flight. An
particular, a wing or a whole aircraft), due to its
aircraft flying at a constant speed will have thrust equal
motion relative to the surrounding air. It must be
to drag.
equal to or greater than the weight of the object
in flight and acting in the opposite direction. Lift
can be increased by increasing the forward speed
of the aircraft or by increasing the angle of
attack
9. DRAG
Theory
Types
Coefficient
Resistance to motion through a fluid. As applied
Drag is generated by nine conditions associated through the
to aircraft and spacecraft passing aerodynamics
A dimensionless number used in
with the motion atmosphere, it is the an aircraft. of the resultant
of air particles over component
to describe the drag of a shape. The drag
There are several types of to relative airflow measured parallel to
force due drag –is independent of the size of the
coefficient, Cd,
form, pressure, skin direction of motion
the
object and is usually determined in a wind tunnel.
friction, parasite, induced, and wave – which are
described below.
Formequation used to calculate drag is: the
The drag and pressure drag are virtually
same type of drag. Form or pressure drag is
D = ½ρV2SCD
caused by the air that is flowing over the aircraft
or airfoil. The separation of air creates
turbulence and results in pockets of low and high
pressure that leave a wake behind the airplane or
airfoil
10. HYPERSONIC FLOW THEORIES
Shock Layer
Entropy Layer
Viscous Interaction
Temperature
Combined Effect
This kind of shock wave is called an oblique
shock because it forms at some angle to the
the leading edge must be rounded or blunted in some way
surface of manufacture and to ease heat
(a shock wave perpendicular to
both for practicality of wedgeproduces friction and fluxes.
travel at high velocities
Whenheat. Part of the kinetic thethe a anormalshocknear the
a thisthe surface is edge, air, of the body's As
travels through energy thin shock).
Close tobodyblunt leadingknown as obliqueregion becomes
Mach number "boundary layer" is
the body surface called theincreases,thatcarried angle
highlymotion isShock theory the air and shock formed.
curved. absorbed by tells us the entropy increases
away
becomes smaller, as increase becomesfigure as
illustrated"freestream"
in the greater
In this a shock,bodyslows down from the
across layer, theand the entropyprocess called viscous
from the air through a
below. increases. at flow near
velocity ofstrength Therefore,Sincedistance between the
the shock the airflow to zero thethe surface. the nose passes
dissipation. However, hypersonic vehicles create
wedge
shock decreases
. The so much heatfactors driving this experiencelayer
two nearly normalsuch high temperatures a much
through a primary surface and thewill boundary thatwith
and shock, it
increasing in compared
growth changeincrease cause chemical the fluid to occur
greater arecan actually speed.
they an in entropy viscosity ofto flow passing through
changes and a
decreasethe density. The result offurther factors is that
the muchin fluid through which they fly from the body
in shallower shock angle these
boundary layer thickness varies as the square of the
centerline
Mach number:
The classical boundary layer grows within this entropy layer
and may be greatly affected by the entropy gradients. In
Thus, as Mach number increases, the boundary layer can that
addition, the entropy layer is a region of strong vorticity
grow rapidly large gradients inhigh velocity flowfield near the
can generate resulting in very the drag.
surface, a phenomenon called "vorticity interaction."
11. ENGINE
Turboprop engine
Turbofan engine
Ramjet
Turbojet engine
An engine that works by expelling a fluid jet
The first type of jet engine to be developed and
backward so that the reaction to this exhaust
one that, various jet engine remained as it
Thepropels inpossible forms, hasinvolving,jet engine
simplest vehicle forward. Both the in
the
widespread useparts. It day. The turbojet1913
was
does, nothe rocketto this was types of reaction
and moving engine are invented in
byinvented by Frank Whittlerocket engine ramjet
René Lorin in France.the in England is selfengine, but whereas Air entering the
and, independently, the forwardOhain
von movement
is compressed and can by Hans a vacuum a in engine
contained solely bywork in
jet
Germany.
of the vehicle.
can only function in the atmosphere.
The principle by which all jet engines (and
rockets) work is the third of Newton's laws of
motions, namely that for every action (force in
one direction) there is an equal and opposite
reaction (force in the opposite direction)
12. APPLICATIONS
Transportation
Military
Commercial Transports:
Hypersonic vehicles in general and waveriders in
Cruise Missiles:
Military Applications:
particular havegreatest proponent of hypersonic
Though developing a man-rated hypersonic
Probably the long been touted as potential
high-speed commercial transports United States
vehicle like those described above the to replace the
travel over the years has been will likely
Concorde. Somework and enormous cost,indicated
require decades of aerospace and 1960s
military. Trends of the 1950s
companies, airlines, and government and higher
militaries aroundaircraft hadwill fly fasterofficials
that military the world to likely have
have proposed conceptsentering service 7fighters
hypersonic cruise vehicles cruising at Machby to 12
to survive, so missiles for high-altitude
capable of carrying passengershigh-speed York
2015. Most current conceptsMachfrom more were
and bombers cruising at for 4 or New
X-43 Hyper-X scramjet test aircraft
to Tokyo in under Although the trend soon fizzled
LoFlyte low-speed handling test vehicle missiles are simple cylinders with no relation to
not uncommon. two hours.
waveriders
and military planners looked to maneuverability
X-30 hypersonic scramjet SSTO concept the military has recently
and stealth for survival,
shown renewed interest in hypersonic flight
Possible Aurora Mach
XB-70 Valkyrie Mach 3 research aircraft 5 reconnaissance aircraft configuration
14. TRANSPORTATION
Concorde fuel efficiency comparison
Aircraft histories
One of thework on SST designs started inthe Tu- ]
Serious problems with Concorde and the midAircraft
Concorde[]
Boeing 747-400
144's operation was first high engineof supersonic
1950s, when the the generation noise and
Supersonic vehicle speeds demand narrower wing levels,
Engines
Jet fighter design shifts entering service.
engine with were significantly between
fuselage associated aircraftsubject to greater stresses and
designs, and arevery high jet velocities used
Structural issues
supersonic and subsonic aircraft. Jet engines, as a
passenger miles/imperial
during take-off, to even 17
more importantly which
flying
temperatures. This leads andaeroelasticity problems, 109
High costs
class,communities near the fuel efficiency at
gallon
over can supply increased airport. SST flexing.
require heavier structures to minimize unwantedengines
supersonic speeds, even though their specific fuel
Takeoff noise and sonic booms a fairly high strongerthrusttherefore heavier)
need
SSTs also require a much specific (and (net
consumption is during at higher speeds. Because
thrust/airflow) greater must be pressurized
structure because their fuselagesupersonic cruise, to to a
their speed over the ground is greater, this
minimize than cross-sectional area and,
greater differentialenginesubsonic aircraft, which do not
passenger miles/US
14
91
decreasenacelle drag. Unfortunately this implies
thereby, in efficiency is less than proportional to
gallon
operate at the high altitudes necessary for supersonic a
speed until well above Mach 2,the engines noisy
high jet velocity, which makes and the
flight. These factors together meant that the empty
consumption per mile isparticularly at low
which of Concorde is lower.
weight per seatcauses problems more than three times that
speeds/altitudes
litres/passenger
16.6
3.1
of a Boeing 747. 100 km and at take-off
Tupolev Tu-144LL