By James Merkel Candidate for Master's Degree in Aerospace Engineering, the University of Texas at Arlington, Fall 2013
University of Texas at Arlington's (UTA) racing partnership with Pointwise during the past three years has resulted in an influx of aggressive aerodynamic development for the UTA Formula SAE race cars. The grid generation software has been crucial in several developments that have resulted in significant improvements to the wing packages on the cars.
Our 2012 wings were designed using both inverse design methods and existing wing elements for a clean sheet four element wing. Then, we developed an in-house optimization tool to place the wing elements in their ideal location for maximum lift coefficient. The UTA team developed a script that automatically meshed the wing using Pointwise and outputted the mesh to STAR-CCM+, which ran the simulation and sent the results to a genetic algorithm which iterated the placement of the airfoils and sent the new model through the analysis loop again. These wings had the highest down force levels ever seen for the UTA cars, producing 550 pounds at 60 miles per hour.
The 2013 car further pushed the envelope of aerodynamics. During the conceptual design phase, the aerodynamics team started with a lap simulation tool developed by one of our team members and studied the effects of lift and drag on lap times around the 2012 competition course. From this we learned two things: more down force ultimately increases cornering speed and decreases lap times but to a diminishing point because straight line speed and fuel economy suffers drastically. Minimizing drag also saw appreciable decreases in lap times on long straights. This evolved to the development of a five element fully active aerodynamics package optimized for maximize down force, as well as minimum drag.
For 2013 we used the same profiles and tools to develop a five element wing using the same criteria of maximizing lift both in ground effect as well as free stream. We were able to gain an additional 30 percent more down force compared to the original four element design. The package as a whole (including underbody diffuser) produced nearly 700 pounds of down force at 60 miles per hour. Then, using a simpler version of our optimization algorithm, we iterated the flap placement for a minimum drag case. Track data has shown up to 0.2 g more acceleration in straights from the drag reduction when opening the wings.
To control the wings, servo motors were integrated into the main plane and a light weight carbon linkage used to connect each flap to the motor, producing a very light weight actuation system. The motors themselves are controlled by a UTA-designed onboard computer that takes various sensory inputs from the car, calculates the optimum wing position based on the track scenario, and outputs the wing position to the front and rear wing in real time without any driver input. Track data has already shown large gains in acceleration as well as higher cornering and straight line speeds. The 2014 car will continue with this system with further development on the controls for the wings to maximize the gains on track.
The Pointwise software and technical support enables the SAE team to aggressively develop cutting edge technology for the Formula SAE series that has garnered a lot of attention both for the university and Pointwise. We look forward to continuing the partnership between UTA Racing and Pointwise for the 2014 competition season.
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