Race Car Aerodynamics

1
Race Car Aerodynamics MER033 Fluid
Mechanics Professor Bruno March 12, 2005
Dave Korim Tim Nonna Drew Moyer
2
Race Car Aerodynamics

• Early Racing
• - Very little attention to aerodynamics
• - Focused mainly on engine and tire performance
• Current Racing
• - Maxed out engine and tire performance
• - Studied Lift and Drag due to inverted wings
• - Focus shifted to
• aerodynamic advantages

3
Race Car Aerodynamics
Purpose Visualize and analyze flow over 1/12th
scale model Mini Cooper Techniques used Wind
tunnel testing - Pressure Measurements - Lift
and Drag Force Measurements - Particle Image
Velocimetry Computational Fluid Dynamics
4
Laboratory Setup
The Wind Tunnel at Union College

• ELD open circuit suction tunnel
• 12-inch square by 22 inch long test section
• Models mounted to dynamometer under the test
  section using a T-shaped bar

5
Laboratory Setup
Wind Tunnel Testing

• Pressure Measurements
• Small hole drilled through model connected to
  pressure taps
• Taps connected to pressure transducer
• 15 pressure taps were used
• Tests carried out at 11.9 m/s (15 hz) and 20.7
  m/s (25 hz)

6
Laboratory Setup
Wind Tunnel Testing
Lift and Drag Measurements - Used model without
pressure taps - Lift and Drag force measured
using dynamometer - Lift and Drag Coefficients
found using
7
Laboratory Setup
Wind Tunnel Testing
Particle Image Velocimetry System - Experiments
performed by students over the summer - Uses
lasers and a high speed camera
8
Laboratory Setup
Computational Fluid Dynamics Analysis
- Uses StarWorks add-in for SolidWorks 3-D
modeling software - Easy visualization of
pressure and velocity fields
9
Results of Wind Tunnel Testing
Pressure Measurements using Pressure Tapped Model
Pressure Coefficient of 1 Stagnation Point
Pressure Coefficient of 0 Free Stream Pressure
10
Results of Wind Tunnel Testing
Down Force and Drag Measurements
11
Results of Wind Tunnel Testing
Lift and Drag Coefficient Measurements
12
CFD Results
Pressure
Velocity
13
PIV and CFD Results
A Comparison of Velocities
PIV
CFD
14
PIV and CFD Results
A Comparison of Streamlines
PIV
CFD
15
CFD Analysis of Drafting
It is often said that racecars reach the highest
speeds while drafting. Why does this happen?

Answer Pressure differences
P
Pressure is higher behind both cars in draft
than single car
16
Questions?