AERODYNAMICS
AND
WINDTUNNELS
DEFINITION
AERODYNAMICS &
WINDTUNNELS
AERODYNAMICS:
IS THE STUDY OF
THE FORCES EXERTED BY
AIR OR OTHER GASES IN MOTION
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AERODYNAMICS & WINDTUNNELS
DESIGN APPLICATIONS
AERODYNAMICS &
WINDTUNNELS
WHY SHOULD WE CARE ABOUT AERODYNAMICS?
BECAUSE IT SIGNIFICANTLY AFFECTS THE PERFORMANCE & SAFETY OF MANY OF
THE THINGS WE USE AND THINGS WE DO:
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AIRCRAFT
SPACECRAFT
AUTOMOBILES AND TRUCKS
ENGINES (Gas turbines, reciprocating engines, etc.)
AIR HANDLING SYSTEMS (fans, blowers, air conditioners, etc.)
BUILDINGS
WIND TURBINES
SPORTS (Ski jumping, speed skating, bicycle racing, windsurfing,
yacht racing, etc.)
InnSol, Inc.
AERODYNAMICS & WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
AERO DESIGN PROCESS
THE SCIENTIFIC
METHOD:
FOR THEORY TO BECOME LAW
IT MUST BE TESTABLE
(otherwise it’s philosophy)
THE WIND TUNNEL
IS THE PRIMARY
TEST VEHICLE FOR
AERODYNAMIC DESIGN
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DESCRIBE
THE
PROBLEM
CREATE AN
ANALYTICAL
MODEL
(DESIGN AND
ANALYSIS)
DEVELOP A
PHYSICAL
DESIGN
UPDATE THE
ANALYTICAL
MODEL
UPDATE THE
PROTOTYPE
PREDICT
PERFORMANCE
AND BUILD A
PROTOTYPE
NO
DO THE RESULTS
MATCH THE
PREDICTION?
TEST THE
PROTOTYPE
YES
CELEBRATE
AERODYNAMICS & WINDTUNNELS
GOVERNING LAWS OF PHYSICS
AERODYNAMICS &
WINDTUNNELS
UNDERSTANDING AERODYNAMICS
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CONSERVATION OF ENERGY
NEWTON’S THIRD LAW OF MOTION
POTENTIAL & KINETIC ENERGY
CONTINUITY EQUATION
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AERODYNAMICS & WINDTUNNELS
ENERGY
AERODYNAMICS &
WINDTUNNELS
THE LAW OF CONSERVATION OF ENERGY
• energy can neither be created nor destroyed, but only changed
from one form into another or transferred from one object to
another
• the total amount of energy in a closed system remains constant
InnSol, Inc.
AERODYNAMICS & WINDTUNNELS
LAWS OF MOTION
AERODYNAMICS &
WINDTUNNELS
NEWTONS THIRD LAW
•
FOR EVERY ACTION THERE IS AN (OPPOSED) EQUAL
AND OPPOSITE REACTION
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AERODYNAMICS & WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
ENERGY TRANSFORMATION
POTENTIAL ENERGY
PE = mass x g x height = weight x height
KINETIC ENERGY
KE = ½ mass x velocity2 = weight x velocity2
2g
InnSol, Inc.
AERODYNAMICS & WINDTUNNELS
DEFINITION
AERODYNAMICS &
WINDTUNNELS
THE FORCES EXERTED BY
AIR ARE MANIFEST IN PRESSURE
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AERODYNAMICS & WINDTUNNELS
CONTINUITY EQUATION
AERODYNAMICS &
WINDTUNNELS
FLOW THROUGH A CONSTRAINED REGION
Continuity Equation
W1 = W2 = Wn
flow = density x area x velocity
1
W=dxAxV
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n
AERODYNAMICS & WINDTUNNELS
2
THE CONCEPT OF PRESSURE
AERODYNAMICS &
WINDTUNNELS
STATIC PRESSURE
OBSERVER MOVING WITH THE AIR
V=0
InnSol, Inc.
AERODYNAMICS & WINDTUNNELS
THE CONCEPT OF PRESSURE
AERODYNAMICS &
WINDTUNNELS
• DYNAMIC (TOTAL) PRESSURE
• Pressure due to velocity of air relative to the velocity of the
object
OBSERVER MOVING WITH THE OBJECT
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AERODYNAMICS & WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
THE CONCEPT OF PRESSURE
RELATIONSHIP BETWEEN STATIC AND TOTAL PRESSURE
Total Temp ≈ Static Temp x (1 + c x V2)
Total Press ≈ Static Press x (1 + c x V2)3.5
Total Press ≈ Static Press x (Total/Static Temp)3.5
InnSol, Inc.
AERODYNAMICS & WINDTUNNELS
DEFINITION
AERODYNAMICS &
WINDTUNNELS
AERODYNAMICS OF WINGS
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AERODYNAMICS & WINDTUNNELS
VELOCITY IN A CONSTRAINED SPACE
AERODYNAMICS &
WINDTUNNELS
VELOCITY IS GOVERNED BY THE CONTINUITY EQUATION
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Density (d) varies with T & P
T & P remain constant unless heat and/or work is added or removed
(conservation of energy), thus d = constant
Therefore: W = constant = d x A x V = constant x A x V
Thus V varies only with A (V = constant/A)
InnSol, Inc.
AERODYNAMICS & WINDTUNNELS
AERODYNAMICS OF WINGS
AERODYNAMICS &
WINDTUNNELS
FLOW OVER A WING
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AERODYNAMICS & WINDTUNNELS
AERODYNAMICS OF WINGS
AERODYNAMICS &
WINDTUNNELS
PRESSURE DISTRIBUTION AROUND A WING
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AERODYNAMICS & WINDTUNNELS
AERODYNAMICS OF WINGS
AERODYNAMICS &
WINDTUNNELS
C
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AERODYNAMICS & WINDTUNNELS
AERODYNAMICS OF WINGS
AERODYNAMICS &
WINDTUNNELS
ANGLE OF ATTACK
As the angle of attack increases
lift increases but so does drag
At some point the air cannot
follow the wing surface and
separates. This causes the wing
to rapidly lose lift, creating stall
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AERODYNAMICS & WINDTUNNELS
AERODYNAMICS OF WINGS
AERODYNAMICS &
WINDTUNNELS
AERODYNAMIC FORCES ON A WING
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AERODYNAMICS & WINDTUNNELS
AERODYNAMIC LOADS
AERODYNAMICS &
WINDTUNNELS
AERODYNAMIC & PHYSICAL LOADS ON AN AIRCRAFT
InnSol, Inc.
AERODYNAMICS & WINDTUNNELS
AERODYNAMICS OF WINGS
AERODYNAMICS &
WINDTUNNELS
LIFT AND DRAG
InnSol, Inc.
AERODYNAMICS & WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
WIND TUNNELS
WINDTUNNELS ARE USED TO:
• DEVELOP EMPIRICAL DESIGN DATA (eg Lift/Drag polars)
• INVESTIGATE AERODYNAMIC PHENOMENA (eg flutter)
• DEVELOP AND VERIFY DESIGNS
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AERODYNAMICS & WINDTUNNELS
WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
WRIGHT BROTHERS
WIND TUNNEL
Critical to the Wright
Brothers’ success was
their wind tunnel.
When they tested their
previous design that
failed expectations they
discovered that its lift
was 1/3 of design
predictions
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AERODYNAMICS & WINDTUNNELS
WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
WRIGHT BROTHERS WIND TUNNEL
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AERODYNAMICS & WINDTUNNELS
WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
LARGE SCALE WIND TUNNELS
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AERODYNAMICS & WINDTUNNELS
WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
OPTIONS
CLOSED LOOP:
Facilitates changes in altitude
(pressure).
Reduces energy consumption.
OPEN LOOP:
Required for engine testing and
testing with inlet additives (eg water,
contamination, etc.
• Ambient
• Inlet air heaters & coolers
• Exhaust pumps to vary altitude
and flight speed.
BLOW DOWN :
• Open configuration
• Closed configuration
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AERODYNAMICS & WINDTUNNELS
WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
BLOW DOWN WIND TUNNELS
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AERODYNAMICS & WINDTUNNELS
VISUALIZING FLOW FIELDS
AERODYNAMICS &
WINDTUNNELS
SCHLIEREN , SHADOW GRAPHS, & LDV
USE AIR DENSITY FOR VISUALIZATION
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AERODYNAMICS & WINDTUNNELS
WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
VERTICAL WIND TUNNELS
NASA LEWIS (GLENN) 5 FT
VERTICAL WIND TUNNEL - 1917
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AERODYNAMICS & WINDTUNNELS
WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
NON - AIRCRAFT
APPLICATIONS
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AERODYNAMICS & WINDTUNNELS
WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
AERODYNAMIC DRAG MEASUREMENT
ON BUILDINGS USING SCALE MODELS
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AERODYNAMICS & WINDTUNNELS
HURRICANES & TORNADOS
AERODYNAMICS &
WINDTUNNELS
WIND LOADS ON STRUCTURES
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AERODYNAMICS & WINDTUNNELS
HURRICANES AND TORNADOES
0
AERODYNAMICS &
WINDTUNNELS
EFFECT OF HIGH
WIND SPEED ON
HOUSE ROOF LOADS
Wind Speed
Wind Speed
Roof Area
Mach #
Total Pressure
Static Pressure
Press Difference
Tot/Stat Press
Load on Roof
mph
ft/s
sq ft
100
150
200
250
300
147
220
293
367
440
2000 2000 2000 2000 2000
0.1311 0.1966 0.2621 0.3277 0.3932
lb/sq in 14.70 14.70 14.70 14.70 14.70
lb/sq in 14.52 14.31 14.01 13.65 13.21
lb/sq in
0.18
0.39
0.69
1.05
1.49
1.012 1.027 1.049 1.077 1.112
tons
25.3
56.3
98.8 151.7 214.0
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AERODYNAMICS & WINDTUNNELS
WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
AERODYNAMICS OF VEHICLES
OBJECTIVE: REDUCE DRAG FOR REDUCED FUEL
CONSUMPTION AND INCREASED SPEED.
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InnSol, Inc.
AUTOMOBILES,
RACE CARS,
MOTORCYCLES &
TRUCKS
AERODYNAMICS & WINDTUNNELS
AUTOMOTIVE APPLICATIONS
AERODYNAMICS &
WINDTUNNELS
MERCEDES BENZ
ENVIRONMENTAL
TESTING
NASA
LANGLEY
FULL SCALE
TESTING
GM WIND TUNNEL
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AERODYNAMICS & WINDTUNNELS
FLOW VISUALIZATION
SMOKE STREAMS
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AERODYNAMICS &
WINDTUNNELS
Smoke
streams
clearly show
flow
separation
and
turbulence –
which means
higher drag
and higher
fuel
consumption
AERODYNAMICS & WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
FLOW VISUALIZATION
HOW TO PREVENT A
CAR FROM BECOMING
AN AIRPLANE
SPOILER
INVERTED WING
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AERODYNAMICS & WINDTUNNELS
FLOW VISUALIZATION
AERODYNAMICS &
WINDTUNNELS
WOOL TUFTS
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AERODYNAMICS & WINDTUNNELS
AERODYNAMICS IN SPORTS
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AERODYNAMICS &
WINDTUNNELS
SKI JUMPING
DOWNHILL RACING
SPEED SKATING
SKY DIVING
BICYCLE RACING
GOLF
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AERODYNAMICS & WINDTUNNELS
WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
SKI JUMPING
V STYLE
CLASSIC
STYLE
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AERODYNAMICS & WINDTUNNELS
WINDTUNNELS
SKY DIVING
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AERODYNAMICS &
WINDTUNNELS
MODERN VERTICAL
WIND TUNNELS – FOR
FUN AND GAMES
AERODYNAMICS & WINDTUNNELS
WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
RACING APPLICATIONS
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AERODYNAMICS & WINDTUNNELS
AERODYNAMICS OF GOLF
AERODYNAMICS &
WINDTUNNELS
WHY DIMPLED GOLFBALLS?
In the early days of golf when the
balls were smooth some golfers
noticed that their old beat up golf
balls drove further than new golf
balls – hence the design of
dimpled ball covers.
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AERODYNAMICS & WINDTUNNELS
AERODYNAMICS OF SPEED SKATING
AERODYNAMICS &
WINDTUNNELS
Under Armour and Lockheed Martin designed gear for
the 2014 Winter Olympics
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AERODYNAMICS & WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
AERODYNAMICS OF DRAFTING
THE LEADER FIGHTS THE HIGHEST DRAG
PEDALING A
BICYCLE AT 152
MPH
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AERODYNAMICS & WINDTUNNELS
AERODYNAMICS
AERODYNAMICS &
WINDTUNNELS
•
EVERYONE IN ONE WAY OR ANOTHER IS AFFECTED BY AERODYNAMICS (BUT
MOST OF US DO NOT REALIZE IT)
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THE PHENOMENAE OF AERODYNAMICS AND THE ATTENDANT LAWS OF
PHYSICS CAN BE DEMONSTRATED WITH A SIMPLE WIND TUNNEL
•
ITS ADVANTAGE IS THAT IT PROVIDES AN INTERESTING “SEE AND TOUCH”
APPROACH WITH CONSIDERABLE OPTIONS FOR STUDENTS TO DEVELOP AN
UNDERSTANDING OF BASIC SCIENCE
InnSol, Inc.
AERODYNAMICS & WINDTUNNELS
AERODYNAMICS &
WINDTUNNELS
AERODYNAMICS
Dennis Barbeau
dennisb@innsolinc.com
InnSol, Inc.
AERODYNAMICS & WINDTUNNELS