The document discusses aerodynamics in cars. It defines key aerodynamic terms like drag, lift, and downforce. It explains how aerodynamic principles like frontal area and drag coefficient affect a car's performance. The document also discusses how car designers use computational fluid dynamics software and aerodynamic devices to reduce drag and optimize airflow over different parts of the vehicle. The goal is to achieve maximum fuel efficiency through improved aerodynamics.

1. Submitted by:
SUDHIR PATEL
Mechanical engineering
3rd year
1900520400058
Submitted to:
Mr. Vipul kumar pathak
INSTITUTE OF ENGINEERING AND
TECHNOLOGY , LUCKNOW
DEPARTMENT OF MECHANICAL ENGINEERING

2. Aerodynamics in Cars
 Aerodynamics is itself a part of fluid dynamics,
which is the study of the properties of a solid object
displace a fluid such as air.
 For the performance of a typical passenger car,
aerodynamics is an important consideration in the
achievement of maximum fuel economy, as well as in
creating auto body styling that is visually appealing.

3. Terms to Know-
Aerodynamics
 Fluid
 Mass
 Aerodynamics
 Drag
 Lift
 Rear Suction
 Down Force
 Frontal Area

4. Fluid
 Air-
 Is a type of fluid such as water that can be directed or
displaced;
 Has mass and is measured in terms of pressure;
 Applies direct and frictional forces to objects in
motion;

5. Principles
 One should be aware of four aerodynamic
principles-
 Drag
 Lift/Down Force
 Drag Coefficient
 Frontal Area

6. Drag
 Drag is a combination of two forces that
will work against the acceleration of your
car.
 Frontal Pressure occurs when tiny molecules of
air hit the front of your car and is forced away to
make room for other molecules to hit it.
 Rear Suction occurs when an empty pocket of air
is created in the back of your car resulting in a
vacuum cleaner effect that tries to pull your car
backward.

7. Air Flow
Rear Suction

8. Lift and Down Force
 Lift is similar to rear suction in that a thin
empty pocket occurs as air passes over a
flat surface causing the car to lift.
 Down Force is due to high pressure in
curved surfaces that causes the car to be
pushed down.

9. Lift and Down Force

10. Drag Coefficient
 Drag Coefficient is a way of expressing
how slippery a car is.
 The drag coefficient (CD) is a measure of
the vehicle's aerodynamic efficiency.

11. FRONT END
Frontal Pressure
Pressure Difference
Minimize Frontal Area
REDUCE Coefficient of Drag

12. Frontal Area
 Frontal Area is the total of all surfaces in the front of
your vehicle which cause drag.
Area = Length x Width

13. Aerodynamic drag
 Aerodynamic drag = (ρ/2) CD * A * V2, where
ρ is air density, A is the projected frontal
area of the body, and V is velocity.
 Even though aerodynamic drag is critically
dependent on the velocity, it is only the
product CD times A that the designer can
control.

14. Past of Aerodynamics
A = frontal
area, b = wheelbase,
CD = drag coefficient

15. REAR END
 Rear Vacuum
Flow Detachment
Turbulence

16. Vehicle Body
 Ergonomics is more and more important in new
cars and for instance the height of new models is
growing. Thus the accessibility is improved.

17. AERODYNAMIC DEVICES
 NASA DUCTS
 Increase rate of flow
 To expose air to areas not exposed to direct air
flow.
 SCOOPS
 Engine Cooling
 Increases Flow Rate of Air
 WINGS
 Produce Down Force
 Reduce Drag

18. SOFTWARES
DEVELOPMENTS IN CFD
ANSYS, CATIA,ALIAS STUDIO
ANALYZE CHANGES DURING DESIGN
PHASE AND DEVELOPMENT
REDUCES TIME TO DEVELOP OPTIMAL
DESIGN
ABLE TO STUDY INDIVIDUAL
ELEMENTS, MORE EFFECTIVE

19. AERODYNAMIC IMPROVEMNTS IN
THE CAR THAT WE ALREADY OWN
Keep your vehicle washed and
waxed
Remove mud flaps behind
wheels
Place license plate out of air flow
Avoid roof-racks or carriers
Close windows, close sunroof

20. Rear View Mirror
A CFD (Computational Fluid
Dynamics) program can be
very useful to optimize the
shape of the rear view mirror.
The pressure distribution on
the side shows clearly how the
rear view mirror influences
the air flow on the side of the
car

21. Conclusion
 This short report leads actually to one major idea
which is that the body of a car only contributes to
roughly half of the total drag.
 The major improvement for future vehicles can be
reached by a smoother design of the underside.
 Another important issue for drag reduction,
certainly later on, will the replacement of rear view
mirrors with cameras for instance.
 New passenger seat configurations, like the driver
seat in the front, two passenger seats in the middle
and one at the rear, would make it possible to design
more streamlined vehicles, paying attention to the
fact that a suitable ergonomics remains.

22. REFERENCES
WEBSITES
www.wikipedia.com
www.cardesignonline.com
[1] Y. Okada et al., “Aerodynamics Evaluation of Road Vehicles in Dynamic
Maneuvering,” in SAE Technical Papers, 2016.
[2] M. Drelas Flight Vehicle Aerodynamics. 2014
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