Reduced aerodynamic drag of road
vehicles by better design of tyre, wheel
and cooling airflow control
Time Period: May 2013- May 2017
Budget: 8,000,000 Sek
Partners: Volvo Cars, Scania, and Volvo
Trucks
Background
45%
30%
25%
Contributions to the aerodynamic drag
from different parts of a passenger car
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Teddy Hobeika
09-Oct-2014
Research Areas
Cooling flow
Wheel aerodynamics
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Teddy Hobeika
09-Oct-2014
Expected Outcomes
Cooling flow focus
on measurements
Wheel aerodynamics
focus on simulations
 Improved method for
 Clarify uncertainties of
cooling flow
measurement
 Quick measuring
capability with little
model preparation time
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Teddy Hobeika
wheel and tyre modeling
in Computational Fluid
Dynamics
 Validate a simulation
procedure that provides
higher accuracy keeping
low resource cost
09-Oct-2014
Research Project Status
 Investigating uncertainties in CFD simulations
with focus on tyre aerodynamics has been carried
out
 Uncertainties introduced with different methods of
modelling wheel rotations have been identified
and methods to overcome them have been
suggested
 Validation of the new methods is still pending
more data and test comparison
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Teddy Hobeika
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Publications
 “Investigation of the Influence of Tyre Geometry on the
Aerodynamics of Passenger Cars” SAE Journal Paper in
“SAE International Journal of Passenger Cars – Mechanical
systems”, Volume 6 Pages 316-325, doi: 10.4271/ 2013-010955
 “Influence of Rims and Tyres on the Aerodynamic
Resistance of Passenger Vehicles” Conference proceeding
paper presented at 11th Conference "Aerodynamik
Kraftfahrzeug", Munich, Germany July 2014,
 “Study of different tyre simulation methods and effects on
passenger car aerodynamics” Conference proceeding paper
to be presented at “International Vehicle Aerodynamics
Conference”, Louborough, UK during October 2014
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Teddy Hobeika
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Example of Tyre Detail Effect
Adding side grooves
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Teddy Hobeika
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Complete Pattern Effect
Test Measurement
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Teddy Hobeika
Slick Tyres CFD
Pattern Tyres CFD
09-Oct-2014
New Method Preliminary Results
Standard Rotation Method
New Rotation Method
Rotating wall boundary
condition on complete
geometry
Rotating wall boundary
condition & Moving
Reference Frame on
purple details
Ground
Ground
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Teddy Hobeika
09-Oct-2014
Cooling Flow Measurements
Example of flow distribution through a radiator
Velocity (m/s)
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Teddy Hobeika
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Future work
 A licentiate is scheduled for May 2015
 Simulations on the way with different rim designs
for analysis of rim tyre interaction
 A second round of wind tunnel tests is planned for
early 2015 to run more configurations to correlate
changes in mass flow to changes in the overall
forces of a the vehicle.
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09-Oct-2014
Thank You for Your Attention
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Teddy Hobeika
09-Oct-2014