This document discusses automotive aerodynamics and provides information on key aerodynamic concepts like lift, drag, thrust, weight, downforce, and how aerodynamic design can improve vehicle performance and fuel efficiency. It explains that aerodynamics aims to reduce drag coefficient through wind tunnel testing and computational fluid dynamics software. Examples are given of drag coefficients for different vehicle models and how even small reductions can significantly improve fuel economy. Aerodynamic devices like wings, spoilers, and diffusers are also outlined.

1. AUTOMOTIVE
AERODYNAMICS
PRESENTED BY:
PRASHANT SAHGAL
U.I.E.T C.S.J.M UNIVERSITY
MECHANICAL (2k11)

2. What does Aerodynamics means?
• Aerodynamics is the study of moving gases (in
this case air) over a body in motion, and how
that air flow will affect the body’s movement
through the flow.

3. BASIC PRINCIPLES TO AERODYNAMICS
A. LIFT
B. THRUST
C. WEIGHT
D. DRAG

4. In an airplane, when:
Drag = Thrust & Weight = Lift
the plane will fly STRAIGHT & LEVEL

5. Aerodynamics History
• Aerodynamics has played an important role in car racing
since the late 1960s, when introduction of the first
inverted wings appeared in some formulas.
• After that time, improved wing systems taken from the
aeronautic technology made leaps forward, improving
consistently lap times, increasing cornering speeds and
vehicle stability.
• With the introduction of the ground effect a few years
later the vehicles used a third element (the under body) to
produce down force, and hence improve the
performances.

6. wing
wing

7. What’s it take to create lift?
Air and motion.
How do we explain lift?
Newton’s Laws of Motion and
Bernoulli’s Principal are used to
explain lift.

8. The Bernoulli Effect:
•If a fluid (gas or liquid) flows around an object at different
speeds, the slower moving fluid will exert more pressure
than the faster moving fluid on the object.

9. Thrust
•A force that moves an object (vehicle) through the air.
•Thrust is generated by the engines of the aircraft or
vehicle
Thrust is used to overcome the drag of an airplane or
car, and to overcome the weight of a rocket.

10. Weight
•A force by which the Earth pulls an object towards its centre.
•Weight = (mass) x (acceleration due to gravity)
Drag
•Aerodynamic force that resists the motion of an object
moving through a fluid (air and water are both fluids).
F=(1/2)CdDV2A
•Cd = Coefficient of Drag
•It is a measure of Aerodynamic
Efficiency of an Automobile.

11. So how much Drag
Coefficient does a car
designer aim for?
•VOLVO 960 (1970 – 1980)
•Cd = 0.36
•VOLVO S80 (2007 – present)
•Cd = 0.28
•TOYOTA PRIUS HYBRID (2013 –
present)
•Cd = 0.26
Reducing the Cd of the car by
just 0.01 can result in a 0.09 kmpl
increase in the fuel economy.
•FORMULA ONE
•Cd = 0.70 ??

12. What is the down force ?
•The term down force describes the downward pressure created
by the aerodynamic characteristics of a car that allows it to
travel faster through a corner by holding the car to the track or
road surface. However it also inverses friction between the tires
and the road surface, thus decreasing maximum velocity.
•It’s a force which arises due to the airflow over and below the
car, which act vertically downward on the car.
•FORMULA ONE Cars are aerodynamically design to generate
maximum downforce.
•High Downforce allows them to race at speed more than
321.9kmph.

13. Aerodynamic Devices
Wings and Spoilers Diffuser
Barge
Board

14. Aerodynamic Analysis in Automobiles
•Wind Tunnels
•Softwares (ANSYS, CATIA)

15. Here are things that can be done to reduce
your vehicle's drag (air resistance):
1.Make the shape of the car so that air flow together
smoothly towards the end of the car
2.Reduce the frontal area of the car by minimizing the
grill making sure that windscreen is as flat as possible.
3.Cover the wheels.

16. • Nissan Maxima 1998
before & after
aerodynamics changes.

17. CONCLUSION
Earlier cars were poorly designed with heavy engines,
protruding parts and box shapes due to which they consume
large quantity of fuel and became unaffordable. All these
factors lead to the development and need of aerodynamic in
the design of an automobile. Now it would be fair to say
that all most all cars are tested for getting the optimum
aerodynamic configuration.