Aerodynamic Performance Improvement of Sport Utility Vehicle using CFD Analysis and Wind Tunnel Experiment By Mrs. Sangeeta Das

1. Presented by
Sangeeta Das
140370711008
Guided by
Prof.Deman Sahu
Mechanical Dept.
PIET
A Mid Semester Review Presentation
On
Aerodynamic Performance Improvement of Sport Utility
Vehicle Using CFD Analysis and Wind Tunnel Experiment

3. Aerodynamics
 A branch of fluid dynamics concerned with studying the motion of air,
particularly when it interacts with moving objects.
 Aerodynamics study can be divided into -
 External Aerodynamics- Flow around solids
Internal Aerodynamics- Flow through passages
 Vehicular aerodynamics study mainly deals with External Aerodynamics.

4. The two enemies of speed are
 Excess Drag ,commonly known as wind resistance .
 Lack of down force or presence of lift .

5. Other Factors contributing to flow field around vehicle
 Boundary Layer-:
In the boundary layer around the vehicle ,the viscosity is dominant and it plays a
major role in drag of the vehicle.
Adds to effective body thickness ,creates skin friction drag
 Separation of Flow Field:-
 Flow separation creates a low pressure turbulent region known as wake.
Wake contributes formation of pressure drag

6. Aerodynamics- Moments and Forces in a moving Vehicle

7. Type of Force Formula Remarks
Lift Force
CL = Lift Coefficient
CD= Drag Coefficient
CS = Side force Coefficient
CPM = Pitching moment Coefficient
CYM = Yawning moment coefficient
CRM = Rolling moment coefficient
A= Frontal area of vehicle
V= Wind Velocity
ρ = Air density
Drag Force
Side Force
Pitching Moment
Yawning Moment
Rolling Moment

8. Challenges Faced by Automobile Industry
 Increasing Fuel price
 World moving towards low carbon economies
 Competition
 Emerging market demand for power hungry yet fuel
efficient SUVs.
Solutions:
Better aerodynamics ,higher will be the speed of the
vehicle .
Better aerodynamics ,less work for engines .
Better aereodynamics ,more stability of the car at high
velocities .

9. Problem Definition

10.  Growing demand of SUV crossovers in India.
 SUVs are oil guzzlers with large engines.
 Large frontal areas and bluff-body shapes increases Cd.
 Additional exterior modifications (fog lamps, roof rails etc)
further increase Cd.
 Matching aesthetics with improved aerodynamics for SUV is a
bigger challenge.
 The recently entered SUV in Indian market Renault Duster has
a great demand even it has a drag co efficent of 0.42 . I aim to
select the best modifications to improve its aerodynamic
characteristics .

11. Objective

12. 1) To modify the external aerodynamics of Renault Duster for improving
various parameters like
 fuel consumption
 drag co efficent
 stability at high speed
by addition of a vortex generator as an add on device .
2) To decide on type and geometry of vortex generators best suited for the
prototype selected for the present study based on car aesthetics , ease of
installation and improvement in aerodynamics.

13. Modeling

14. The die cast model of Renault Duster obtained from
Renault France as shown below.
The model is a 1:43 scale down model.

15.  The dimensions available in the public domain as well as
practically measured have been verified with the die cast
model and a 3D model of the car is made using CREO
software .

16. The model used for the wind tunnel test is 3D printed in
Vexma Technologies Pvt. Limited. It is a 1:20 scale down
simplified model based on the 3D CREO model .
3D printed car model
3D printed VG

18. Wind tunnel facility located at SVIT ,Vasad ,Aero.Deptt.

19. Test Section

20. Anemometer &Digital Force Indicator
Multitube manometer setup

21. Type Open return wind tunnel
Test Section 300x300x1000 mm
Blower fan 5 blades -Aluminium die cast
A.C.Motor 3 HP -2880RPM
Speed Variation 10% to 100% frequency Drive Controller
Air Velocity 2-30 m/s
Multitube manometer 16 PVC tubes,0-90 inclination ,acrylic single block
Anemometer Velocity range:0-30m/sec:Display:Digital
Strain gauge balance Two channel, Capable of measuring lift force upto 20
kg, drag force up to 20 kg
Air Length 9:5 m
Digital force indicator Two channel, Capable of measuring lift force upto 20
kg, drag force up to 20 kg
Lift/Drag force sensor 0-20kg-2 channel/0.01kg resolution

22. Car model with pressure tappings
Pressure
Point 2
Pressure
Point 3
Pressure
Point 4
To measure the static pressure on
the car body,0.4 mm diameter
holes are drilled on the center line
of the vehicle body starting from
the front end along the roof to the
rear end of the vehicle.
Pressure
Point 2

23. The car model is mounted in the
test section connecting dirctly to
the digital force sensors .
The wind tunnel tests are
performed at different velocities
within a range of 10 to 25 m/s .
The pressure distribution
readings are taken along the
symmetry plane through the multi
tube manometer.

24. Tapped pts.
Velocity Dists.(m/s)
10 15 20 25
1 -10 -12 -16 -19
2 15 18 23 25
3 -5 -7 -11 -14
4 -12 -15 -18 -21
Tapped pts.
Velocity Dists.(m/s)
10 15 20 25
1 -10 -12 -14 -18
2 13 16 23 25
3 -5 -7 -11 -14
4 -5 -8 -11 -15
Pressure values in mm at different tapping points at different
velocities for base model
Pressure values in mm at different tapping points at
different velocities with VG

25. -80
-60
-40
-20
0
20
40
60
80
100
1 2 3 4
25
20
15
10
Pressure distribution at different
velocities for base model

26. -80
-60
-40
-20
0
20
40
60
80
100
1 2 3 4
25
20
15
10
Pressure distribution at different
velocities with vortex generator

28. 0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
10 15 20 25
With VG
Base model
Comparison of lift force for base model and VG

29. Work Particulars Jun July Aug Sept Oct Nov
2015-2016 WEEK
3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 4 1 2 3 4
Problem Selection
Confirmation of
dissertation topic
Objective of Project
Literature review
Scope of work
Definition of
problem

30. Work Particulars-2015-
2016
Dec. Jan. Feb. March April may
WEEK
1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2
Purchasing of original
die cast model &
dimension varification
Modelling of car body
using Pro-E
Preparation of 3D
printed model for
experiment
Experiment in Wind
Tunnel
Analysis using ANSYS
Preparation for final
presentation

31. Thank you