Design and Analysis of a Car Rear Wing
Published on September 7, 2022
Overview
Ever since I started following F1 in 2018, I have been fascinated with how much downforce the F1 cars can produce to glue the vehicles down to the floor, especially during cornering. I also recently acquired a Flow Simulation add-in license for Solidworks and wanted to learn how to use CFD – so I decided to design a rear wing for a car with a focus on increasing downforce while minimizing drag.
I first analyzed and optimized an ideal 2D airfoil shape and found the optimal angle of attack that produced the maximum downforce in CFD. Then, I created the 1.8 m long wing and performed a 3D CFD analysis at 200 KPH free stream velocity. The maximum downforce the rear wing was able to produce was 2,350 N with 540 N of drag. Adding endplates allowed the wing to increase the downforce produced up to 2,700 N while keeping the drag down to 420 N. The swan neck mount design was chosen because of its ability to disrupt the airflow going over the negative pressure side of the wing less than a conventional mount design. With the swan neck mount, the downforce created was only 2,290 N but the drag decreased to 410 N.
Lessons Learned
The airfoil shape can be optimized. To increase iterations during the 2D analysis of the airfoil shape, I opted to use relations to constrain the location of the maximum camber instead of importing the XY coordinates for NACA airfoils from www.airfoiltools.com – the airfoil used in the analysis is a faux NACA 5314 airfoil.
The fillet of the leading edge in the negative pressure side of the wing produces a positive pressure area due to the geometry. This decreases the suction that the negative pressure side of the wing can produce. Smoothening out this transition to be more streamlined will likely result in better airflow over the negative pressure side and increase the overall downforce the wing can produce.
The swan neck mount design can also be optimized. Right now, the swan neck mount is just a symmetrical rounded rectangular shape and it is producing turbulent flow to the negative pressure side of the wing. I believe designing a more streamlined swan neck mount can send a much cleaner airflow to the negative pressure side of the wing which can stick to the surface much better because of less turbulent flow conditions.
