 Aerodynamic Coefficients
CD: 0.324 +/- 0.002 CL: -0.396 +/- 0.002 Results: The increase in drag caused by the removal of the tailgate was unexpected and seems counterintuitive. We believe when the tailgate is in the upright position, there is a bubble of slowly circulating air in the truck bed that forms a virtual bed cover of air and keeps most of the airflow around the truck from hitting the bed bottom and the inside of the tailgate. Removing the tailgate does not allow this bubble to form, which allows the faster moving air to interact aburptly with the bed bottom. This is very non-aerodynamic and causes the increase in drag. After testing was completed, we researched this phenomenon and found that results of a similar study confirm our hypothesis. The top image is a picture of the truck with no tailgate. The graph below shows the convergence of the drag coefficient as Reynolds number is increased. |