Complete data are available in an Excel spreadsheet. Other formats are available on request.
For the wind tunnel frequency range of 10 to 26 Hz, the air velocity increased linearly from about 9 to 22 m/s. There is no "frequency" for real race car air flow. It is dependent on velocity, all calculations and graphs are based on air speed rather than wind tunnel frequency. The lift force roughly follows a linear relationship with the velocity. The force on the model car ranges from .30 to -.17 newtons on the wind tunnel air speeds. The drag force decreases with speed, but unlike the lift, it increases in magnitude. It has a fairly constant value for velocities up to 14 m/s, and after that, increases dramatically. The dimensionless coefficient of lift follows a trend similar to its corresponding force. C_L decreases, but not in a linear manner. Instead, it seems to trace out a portion of a hyperbolic graph. In contrast with the drag force, the drag coefficient decreases in magnitude up to 14 m/s, at which point it levels off. More detailed graphs with error bars can be found in the complete data. |