Aerodynamics

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Aerodynamics Motion
STEM Foundations
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Aerodynamics Motion
Essential Question for the Lesson How does the
shape of an object effect air flow around that
object?
3

• Form Follows Function
• Form shape of any object should follow its
  function purpose
• Ex. Speed, Flight, Shipping, High Altitude
• You will be building a car for speed
• How can we achieve speed?

4

• Form Follows Function
• Fixed factor-Thrust
• /- .04 gram fixed CO2 cartridge
• You can control mass friction
• Newton's 2nd Law of Motion
• Fma
• With a given force, if the vehicle is lighter and
  streamlined (reduce in friction) it will go
  faster.

5

• Aerodynamics
• What is it?
• Study of airflow the forces involved when an
  object moves through the air or when air moves
  past an object.
• Four major forces affect airflow
• Lift, gravity, thrust drag
• These forces oppose each other
• Newton's Third Law
• For every action there is an equal opposite
  reaction.

6

• Aerodynamics
• Drag opposes Thrust
• Friction
• Resistance of movement between two touching
  surfaces. Loss of efficiency in the form of
  heat.
• What causes friction on a moving car?
• How can we reduce friction?

7

• Aerodynamics
• Aerodynamic Drag
• Caused by shape, form, surface finish, body
  protrusions, projected frontal area
• PFA is the air being displaced as the vehicle
  moves forward
• Measured in sq.

8

• Coefficient of Drag
• Cd is the amount of resistance vehicles encounter
  as they move through the air.
• Lower the Cd more aerodynamically efficient
• Which vehicles do you think would have a lower
  Cd?

9

• Skin Friction
• Is drag due to surface finish.
• Air acts very similar to water and is a viscous
  fluid.
• Viscous means having a quality of sticking or
  adhering.
• As a vehicle is in motion air will stick to it.

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Skin Friction
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• Streamline Laminar Flow
• Streamline
• The movement of air around a fixed or moving
  structure.
• What is the most streamlined shape?
• Teardrop
• What makes a streamlined shape
• Smooth surfaces no abrupt corners, gradually
  tapered surfaces.

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• Streamline Laminar Flow
• Laminar
• Straight and even airflow around an object
• Can be improved by designing a sleek, continuous,
  smooth flowing, uninterrupted structural skin on
  a vehicle.

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Streamline Laminar Flow
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• Separation Eddies
• Separation
• Takes place when air movement around an object is
  not streamlined and causes the boundary layer to
  break up and swirl.
• Eddies Vortices
• The swirls that are created from the separated
  airflow.
• Absorbs energy from the moving object and reduces
  efficiency.

15

• Parasite Drag
• Drag caused by irregularities or protrusions on
  the outer surface of a vehicle.
• These protrusions cause eddies and vortices.

16

• Parasite Drag
• What are some body protrusions on this 1957 Chevy
  BelAir?

17

• Wind Tunnels
• Wind Tunnels
• Machines used to measure aerodynamic efficiency
• Use giant fans to pull or blow air over an object
  measures forces such as lift and drag
• Airflow Visualization
• Smoke or tuffs of string tied to the objects can
  be used to help engineers visual airflow over an
  object in a wind tunnel.

Wind Tunnel Video
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Review

• What are the four major forces that effect
  airflow?
• Friction is a loss of efficiency in the form of
  what?
• What is the most aerodynamic shape?
• Straight and uninterrupted airflow is known as
  what?

Lift, Drag, Thrust, Gravity
Heat
Teardrop
Laminar airflow
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Review Worksheet

• Read pages 12-14 in Aerodynamics packet and
  complete the review worksheet and crossword
  puzzle. Submit your work for credit.